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V 


DENTAL  PROSTHESIS 

AND 

METALLURGY. 


WARREN. 


JUST  READY— SECOND  EDITION— ILLUSTRATED. 


A  Compend  of  Dental  Pathology 
and  Dental  Medicine. 

Containing  all  the  most  noteworthy  points  upon  these  subjects, 
INCLUDING  A  SECTION  ON  EMERGENCIES. 


BY  GEORGE  W.  WARREN,  D.D.S., 

Chief  of  Clinical  Staff  Pennsylvania  College  of  Dental  Surgery,  Editor  Oj 
Richardson' s  Mechanical  Dentistry. 


Illustrated.     i2mo.    Cloth,  $1.00  ;  Interleaved,  for  Notes,  $1.25. 


Jg^15  This  book  contains  a  vast  deal  of  practical  information  in 
a  concise  shape.  It  will  be  found  invaluable  to  the  student,  and  of 
great  use  to  the  Dental  Practitioner  who  wishes  to  keep  himself 
informed  of  the  latest  methods  of  investigation  and  treatment. 


JUST  READY,  NEW-SIXTH-EDITION, 


RICHARDSON'S 
MECHANICAL  DENTISTRY. 

THOROUGHLY  REVISED  AND  REWRITTEN. 


BY  GEORGE  W.  WARREN,  D.D.S., 

Clinical    Chief  Pennsylvania    College  of  Dental  Surgery,   Philadelphia. 


600  Illustrations.    Octavo.    Cloth,  $4.50 ;  Leather,  $5.50. 


The  Dental  Cosmos  says  of  this  new  edition : — 

"  The  present  edition  of  Richardson  is  practically  a  new  book.  In  all  depart- 
ments it  has  been  carefully  brought  into  accord  with  present  needs,  and  is  fully 
up  to  the  latest  thought  in  its  field.  The  chapters  upon  fuels,  the  application 
and  generation  of  heat,  metals  and  alloys  used  in  the  work,  impressions  of  the 
mouth,  dies  and  counter-dies,  etc.,  are  full  and  satisfactory.  The  section  upon 
crown  and  bridge  work,  embracing  over  two  hundred  pages,  is  a  volume  in 
itself."  

P.   BLAKISTON,  SON    &   CO.,  PHILADELPHIA. 


C  0  M  P  E  N  D 


OF 


DENTAL  PROSTHESIS 


AND 


METALLURGY. 


liY 

GEO.  W.  WARREN,    D.D.S., 

CHIEF  OF  THE   CLINICAL  STAFF,  PENNSYLVANIA  COLLEGE   OF  DENTAL  SURGERY 

PHILADELPHIA;    AUTHOR    OF   "A    COMFEND    OF    DENTAL    PATHOLOGY 

AND    DENTAL    MEDICINE;"    EDITOR    OF    "  RICHARDSON'S 

MECHANICAL   DENTISTRY,"    ETC.,    ETC. 


WITH  ONE  HUNDRED  AND  TWENTY-NINE 
ILLUSTRATIONS. 


PHILADELPHIA: 
P.    BLAKISTON,    SON    &    CO., 

I  O  I  2     WALNUT     STREET. 
1894. 


Copyright,  1894,  by  P.  Blakiston,  Son  &  Co. 


PRESS  OF  WM.   F.   FELL  8l  CO., 

1220-24   SANSON!    ST., 

PHILADELPHIA. 


NOTE. 


For  assistance  in  the  preparation  of  this  manual,  the 
author's  thanks  are  due  Mr.  Alfred  E.  Hunt,  President 
of  the  Pittsburgh  Reduction  Co.,  for  data  concerning 
the  latest  experiments  with  Aluminum,  and  Mr.  E.  A. 
Kretschman  for  suggestions  in  reference  to  the  Electro- 
deposition  of  metals. 

He  is  also  indebted  to  the  writings  of  well  known 
authorities,  to  which  he  has  frequently  referred ;  nota- 
bly those  of  Profs.  Wilber  F.  Litch,  Henry  Leffmann, 
S.  H.  Guilford,  Chas.  J.  Essig,  Joseph  Richardson,  and 
Drs.  James  W.  White,  Edward   C.   Kirk,  John  Allen, 

and  Theo.  F.  Chupein. 

Geo.  W.  Warren, 
i 718  Walnut  St.,  Philadelphia. 
September,  i8g4. 


CONTENTS. 


PAGE 

Introduction, 9 

Examination  of  the  Mouth, II 

Materials  Employed  in  Obtaining  Impressions  of  the  Mouth,  .  18 

Methods  of  Taking  Impressions  of  the  Mouth, 20 

Plaster  Models  or  Casts, 30 

The  Selection  and  Arrangement  of  the  Teeth, 43 

Flasking,  Vulcanizing,  and  Finishing  the  Rubber  Base,  ...  64 

Celluloid  as  a  Dental  Base, 85 

Artificial  Dentures  Constructed  by  the  Swaging  Process,  .    .    .  102 

Artificial  Dentures  upon  a  Cast  Metal  Base, 129 

Artificial  Dentures  upon  an  Electro-deposited  Base,     ....  132 

Deposition  of  Copper, 132 

Deposition  of  Silver, 134 

Deposition  of  Gold, 137 

Artificial  Dentures  Formed  by  the  Continuous-Gum  Process,  •  139 

Metallic  Base  with  Rubber  or  Celluloid  Attachment,    ....  147 

Obturators  and  Artificial  Velum,      151 

Interdental  Splints, 160 

Appliances  for  the  Correction  of  Dental  Irregularities,     ...  167 

Crown-  and  Bridge- Work, 185 

Bridge  Dentures, 209 

Dental  Metallurgy, 219 

Gold,  General  Properties,  etc., 222 

Preparing  Alloys  of  Gold  for  Dental  Purposes,      ....  223 

Refining  Gold, 230 

Platinum, 236 

vii 


Vlll  CONTENTS. 

PAGE 

Silver, 239 

Aluminum, 243 

Zinc, 247 

Lead, 247 

Tin, '  248 

Copper, 249 

Iron, 251 

Antimony, 254 

Bismuth, 254 

Mercury, 255 

Amalgams, 257 

Alloys,  their  Treatment  and  Behavior  in  the  Process  of 

Compounding, 259* 


DENTAL  PROSTHESIS 


AND 


METALLURGY. 


INTRODUCTION. 

The  thoroughly  qualified  dentist  is  to  some  extent 
physician,  surgeon,  artist,  and  mechanic.  In  these 
pages  we  are  to  set  aside  the  operative  and  medical 
aspect  and  consider  the  principles,  methods  and  mate- 
rials involved  to  develop  in  him  the  mechanic,  the 
artisan.  In  our  study  of  dental  prosthesis  we  must 
recognize  at  once,  that  the  fundamental  principles 
of  mechanics  are  based  upon  established  laws — they 
are  scientific,  that  is,  they  agree  with  or  depend  upon 
the  rules  or  principles  of  science.  Also  that  dental 
mechanics  embodies  unusual  art  possibilities,  and  that 
the  esthetic  requirements  are  met  in  accordance  with 
the  artistic  conception  and  culture  of  the  dentist. 

Before  taking  up  the  processes  and  methods  apper- 
taining to  this  department  of  dental  practice,  some 
general  reflections  may  be  advantageous  to  the  student. 

9 


IO  DENTAL    PROSTHESIS   AND    METALLURGY. 

Dr.  Richardson,  in  his  Treatise  on  Mechanical  Dentistry, 
says:  "The  untimely  or  premature  loss  of  the  natural 
teeth  may  be  ascribed  to  a  number  of  diverse  causes. 
Multitudes  are  lost  in  consequence  of  abuse  or  neglect, 
or  the  dread  of  pain  so  commonly  associated  with 
the  means  employed  in  their  preservation ;  many 
from  unavoidable  accident ;  and  countless  numbers 
are  sacrificed  through  the  incompetency  and  .  dis- 
honesty of  ignorant  and  unscrupulous  persons  who, 
in  one  guise  or  another,  infest  and  prey  upon  com- 
munities." 

Though  the  intelligent  practitioner  finds  it  necessary 
to  extract  many  teeth,  it  is  in  nearly  all  cases  due  to 
negligence  on  the  part  of  the  patients  or  their  parents, 
the  teeth  having  been  permitted  to  remain  in  a  diseased 
condition  until  such  procedure  is  necessary,  and  it  is 
fair  to  assume  that  the  time  will  never  come  when 
thousands  of  teeth  will  not  be  sacrificed.  We  cannot 
transgress  Nature's  laws  without  paying  the  penalty. 
This  field,  then,  will  ever  be  a  growing  one,  not  in  the 
number  of  artificial  dentures  required,  perhaps,  but 
in  fulfilment  of  the  possibilities  of  the  prosthetic  and 
esthetic. 

While  it  is  the  distinctive  office  of  prosthetic  den- 
tistry to  devise  and  perfect  means  and  appliances  for 
correcting  the  deformities  caused  by  the  loss  of  the 
natural  teeth,  the  first  step  in  all  cases  is  to  make  a 
thorough  examination  of  the  mouth,  so  that  more  in- 
telligent advice  may  be  given  as  to  the  form  and  class 
of  denture  to  be  inserted. 


EXAMINATION    OF   THE    MOUTH.  IT 

EXAMINATION  OF  THE  MOUTH. 

In  our  special  field  of  human  endeavor  the  highest 
order  of  qualification  is  demanded  for  the  fulfilment  of 
its  diversified  and  complex  requirements ;  and  one  who, 
in  examining  the  mouth,  is  not  able  to  take  in  all  the 
conditions,  or  who  lacks  sufficient  judgment  to  decide 
just  what  form  of  appliance  will  be  the  most  comfort- 
able and  useful  in  each  individual  case,  is  no  more 
equipped  for  the  practice  of  dentistry  than  is  the 
physician  who  is  not  a  good  diagnostician,  for  the 
practice  of  his  profession. 

In  examining  the  mouth  the  following  conditions 
should  be  considered :  first,  where  only  a  few  teeth  are 
lost,  whether  a  removable  denture  in  the  form  of  a 
plate,  or  a  removable  or  immovable  bridge  should  be 
advised  ;  and  where  all  the  teeth  are  lost,  or  where  an 
impression  is  required  for  a  plate  of  any  kind,  we 
should  consider  the  shape  of  the  jaws,  whether  long  or 
short,  deep  or  shallow,  hard  or  soft;  whether  the 
alveolar  ridge  is  solid  or  in  a  soft  and  flexible  condition  ; 
whether  the  relative  position  of  the  jaws  are  correct,  or 
the  upper  or  lower  protrude ;  and  then  if  there  are  any 
remaining  teeth,  whether  or  not  they  can  be  made  useful 
or  whether  they  would  interfere  with  the  comfort,  use- 
fulness and  artistic  appearance  of  the  artificial  denture. 

To  illustrate  and  impress  upon  the  student's  mind 
the  importance  of  sound  judgment  at  all  times,  we  will 
call  attention  especially  to  two  or  three  deformities. 

A  gentleman  called  upon  us  for  our  opinion  as  to 


12 


DENTAL    PROSTHESIS    AND    METALLURGY. 


whether  an  artificial  denture  could  be  constructed  so 
that  he  could  use  it  for  mastication.  The  accompany- 
ing illustration  (Fig.  i)  shows  the  condition  of  his 
superior  maxillary.  The  alveolar  ridge  in  the  anterior 
part  of  the  mouth  was  completely  absorbed,  while  the 
posterior  portion  in  the  region  of  the  tuberosities  was 

Fig.  i. 


very  much  hypertrophied.  He  reported  that  within 
three  years  he  had  had  plates  constructed  by  as  many 
different  dentists,  but  without  receiving  any  permanent 
satisfaction.  It  was  the  writer's  pleasure  to  insert  a 
denture  which  has  been  worn  for  over  six  years  with 
much  comfort  and  usefulness.  The  secret  of  our  suc- 
cess in  this  case  lies  (i)  in  securing  an  accurate  cast; 


EXAMINATION    OF    THE    MOUTH. 


!3 


(2)  in  the  location  of  the  plate  line  and  in  carving  the 
cast  sufficiently  at  the  soft  points,  and  (3)  in  securing 
a  correct  articulation.  Our  plate  line  and  the  extent  of 
the  carving  is  shown  in  the  illustration. 

One  of  the  most  frequent  deformities  is  the  lack  of 
symmetry  in  the  alveolar  ridge.  For  instance,  in  a 
large  percentage  of  cases,  it  will  be  found  that  there  is 


Fig    2. 


a  greater  depression  upon  the  left  side  of  the  mouth 
than  upon  the  right.  Fig.  2  shows  a  base-plate  which 
has  been  formed  over  such  a  model.  Dr.  Eugene 
Talbot  writes  that  out  of  298  examinations  of  models 
he  found  268  with  marked  depressions  upon  the  left 
side,  and  24  with  the  depression  upon  the  right  side, 
and  only  6  cases  showing  both  sides  to  be  alike. 

This  depression  is  not  so    apparent   upon  a   casual 


14  DENTAL    PROSTHESIS   AND    METALLURGY. 

glance,  for  it  is  not  so  much  in  the  alveolar  process  as 
in  the  maxillary  bones.  Dr.  Haskell  says  of  this,  that 
a  plate  swaged  upon  a  model  from  an  impression  taken 
high  over  the  region  of  the  cuspids  (as  should  always 
be  done)  shows  at  once  the  depression  of  the  left  side, 
which  occurs,  to  a  greater  or  less  extent,  in  95  per  cent, 
of  cases.  The  difference  becomes  apparent  in  arrang- 
ing artificial  teeth.  Every  dentist  of  experience  must 
have  observed  that  greater  length  of  teeth  and  gums  is 
required  upon  the  left  side  than  upon  the  right.  How 
often  it  is  seen  that  the  left  side  of  the  lip  rises  higher 
in  talking  and  laughing,  than  the  right  side.  The  dif- 
ference in  the  two  sides  of  the  lower  jaw  does  not  occur 
as  often,  but  is  apparent  in  the  divergence  of  the  left 
side  from  a  line  drawn  through  the  center  of  the  model, . 
so  that  the  posterior  teeth  on  that  side  must  be  set 
farther  in  upon  the  plate. 

This  deformity  should  be  recognized  and  studied  by 
every  operator,  especially  those  engaged  in  arranging 
artificial  teeth  and  waxing  up  plates,  for  the  purpose  of 
restoring  the  contour  of  the  face. 

A  case  showing  to  what  extreme  the  dentist  may  be 
called  upon  for  services,  and  illustrating  anew  the  need 
of  sound  judgment  in  determining  the  best  course  to 
pursue,  is  that  presented  to  the  American  Dental  Asso- 
ciation by  Dr.  J.  D.  Patterson,  of  Kansas  City. 

The  patient,  a  member  of  the  United  States  Cavalry, 
in  a  battle  with  the  Indians,  was  struck  upon  the  lower 
maxilla  with  a  ball  from  a  Winchester  rifle.  The  an- 
terior part  of  the  maxilla,  from  the  second  bicuspid  upon 


EXAMINATION    OF    THE    MOUTH. 


!5 


the  left  side  to  the  second  molar  on  the  right  was  badly 
shattered,  and  at  a  point  in  the  region  of  the  right 
cuspid  for  the  space  of  about  six  lines,  the  bone  was 
entirely  gone  (see  Fig.  3,  A,  B)  leaving  the  remaining 
posterior  parts  freely  movable.  This  loose  bone  and 
the  teeth  had  been  removed,  and  the  case  had  been  in 

Fig.  3. 


a  surgeon's  hands  for  six  weeks,  when  he  was  brought  to 
Dr.  Patterson  presenting  the  following  condition. 

The  outside  wounds  had  healed  with  considerable 
cicatricial  tissue ;  the  left  fragment  of  the  maxilla  was 
easily  movable,  and  an  abscess  was  discharging  freely 
upon  the  face  opposite  the  loose  end  with  another  ab- 
scess opening  under  the   chin   near  the  symphysis  ;   the 


1 6  DENTAL    PROSTHESIS   AND    METALLURGY. 

left  side  of  the  jaw  was  much  firmer  than  the  right,  but 
had  healed  far  inside — about  a  half-inch  from  the  nor- 
mal position.  There  was  still  considerable  swelling, 
and  small  spiculae  of  bone  frequently  made  their  way  to 
the  surface.  The  lower  jaw  was,  of  course,  entirely 
useless,  and  was  kept  tightly  bandaged  to  the  upper. 

The  first  treatment  instituted,  as  described  by  Dr. 
Patterson,  is  as  follows  :  "I  found  that  a  bridge-splint 
placed  upon  the  parts  as  presented  would  result  in  re- 
taining the  incorrect  position  of  the  left  side,  and  that 
pressure  brought  to  bear  or  force  the  pieces  apart  would 
result  in  still  greater  deformity,  because  the  more  easily 
movable  right  fragment  would  give  way,  leaving  the  left 
in  its  former  position.  The  first  step  then  was,  if  pos- 
sible, to  remedy  the  distorted  position  of  the  left  side. 
I  proceeded  as  follows :  I  banded  the  first  lower  molar 
upon  the  right  side  and  also  the  first  upper  molar  upon 
the  same  side,  attaching  lugs  to  the  bands  for  the  recep- 
tion of  a  screw,  and  firmly  screwed  them  together.  I 
then  placed  a  jack-screw  upon  these  molars  on  the  pal- 
atal side  and  against  the  molar  on  the  left  side,  and 
forced  that  side  into  its  correct  position,  which  had 
been  determined  by  models  beforehand.  I  then  banded 
the  upper  and  lower  teeth  upon  this  side  as  upon  the 
other,  and  screwed  them  firmly  together. 

"I  then  dismissed  the  patient  for  ten  weeks,  the  in- 
tention being  to  overcome  the  growth  of  cicatricial  tissue 
which  forced  the  left  side  against  the  tongue.  I  believed 
the  abscesses  were  caused  by  the  movement  of  the  loose 
ends  upon  the  soft  tissue,  and  the  result  proved  that 


EXAMINATION    OF    THE    MOUTH.  I  7 

this  surmise  was  correct,  as  they  soon  healed  after  the 
parts  were  secured  firmly  to  the  upper  jaw. 

"At  the  end  of  three  months  the  patient  returned. 
He  reported  himself  as  very  comfortable,  save  only  that 
he  was  limited  entirely  to  soft  foods.  On  the  removal 
of  the  bands  the  left  side,  after  two  or  three  days, 
swerved  slightly  inward  and  there  remained,  not  quite 
but  nearly  in  correct  position.  I  then  proceeded  to 
make  the  splint-bridge  shown  in  the  accompanying  illus- 
tration (Fig.  4)." 

Fig.  4. 


The  details  of  making  such  an  appliance  of  course 
cannot  be  considered  at  this  time.  It  is  sufficient  to 
say  that  this  denture,  which  serves  as  a  splint  as  well  as 
a  bridge,  restored  the  contour  of  the  lower  lip  and  lost 
portion  of  the  jaw,  and  at  the  last  report  was  being 
worn  with  entire  satisfaction.  This  case  is  given  here 
as  it  shows  the  necessity  of  good  judgment  upon  the 
part  of  the  dentist,  and  how,  when  possessing  the  re- 
quirements, he  can  supplement  the  best  that  the  sur- 
geon can  do. 

After  the  mouth  has  been  restored  to  a  healthy  and 


iS  DENTAL    PROSTHESIS    AND    METALLURGY. 

suitable  condition,  and  where  an  artificial  denture  is  to 
be  inserted,  the  next  procedure  is  to  secure  as  perfect 
an  impression  as  is  possible,  as  such  an  impression  with 
a  correct  articulation  is  the  foundation  upon  which  we 
have  to  work.  But  before  taking  up  the  methods  of 
securing  impressions  of  the  mouth,  we  will  consider  the 
different  materials  used  for  that  purpose,  and  in  doing 
so  they  will  be  classified  according  to  their  excellence. 


MATERIALS    EMPLOYED    IN    OBTAIN- 
ING IMPRESSIONS   OF  THE  MOUTH. 

Plaster  -of-  Paris . — Plaster  •  of-  Paris,  technically, 
calcium  sulphate  (CaSOJ,  has  been  employed  for  many 
years  for  taking  impressions  of  the  mouth,  and  is  in 
nearly  all  cases  the  very  best  material  known  for  that 
purpose.  Plaster-of- Paris  occurs  in  nature  as  a  mineral 
called  gypsum.  This  differs,  however,  from  the  dried  cal- 
cium sulphate  of  commerce  (sulphate  of  lime  or  plaster- 
of- Paris)  in  that  it  contains  two  molecules  of  water  of 
crystallization  (CaS04,2H20).  The  water  of  crystalli- 
zation is  driven  off  at  39  2°  F.,  leaving  a  white,  opaque 
mass,  which  is  then  known  as  plaster-of-Paris.  This, 
however,  readily  recombines  with  water,  forming  a 
hard  mass.  The  setting  process  is  regarded  as  a  chemi- 
cal action,  the  water  being  absorbed  in  proportion  of  two 
molecules  to  one  of  the  plaster.  The  result  being  chemi- 
cally the  same  as  it  is  in  its  native  state,  CaS04,2H20. 

Professor  Henry  Leffmann  says:    "The  facility  with 


MATERIALS    EMPLOYED    IN    TAKING    IMPRESSIONS.      1 9 

which  this  combination  occurs  depends  largely  on  the 
care  which  has  been  taken  in  preparing  the  plaster.  If 
it  has  been  too  highly  heated,  the  power  of  taking  up 
water  is  lost.  The  presence  of  impurities  also,  of  course, 
interferes  with  the  setting  qualities.  It  is  well  known 
that  the  many  saline  substances,  e.  g.,  common  salt, 
hasten  the  setting,  but  the  exact  cause  of  this  is  not 
definitely  known.  In  the  case  of  common  salt  a  double 
composition  occurs  to  a  slight  extent,  by  which  calcium 
chlorid  and  sodium  sulphate  are  formed.  When  a  solu- 
tion of  the  so-called  liquid  silex,  which  is  sodium  sili- 
cate, is  put  on  a  plaster  cast,  a  similar  reaction  often 
occurs,  forming  sodium  sulphate  and  calcium  silicate, 
and  the  sodium  sulphate  appears  on  the  surface  of  the 
cast  in  white,  moss-like  tufts." 

Plaster-of-Paris  has  taken  its  name  from  its  abounding 
at  Mont-Martre,  near  Paris,  this  being  the  most  import- 
ant deposit  known. 

Modeling  Composition. — Modeling  composition 
or  compound  is  composed  of  gum  dammar,  stearin,  and 
French  chalk,  with  carmin  as  a  coloring-material,  and 
a  little  perfume  to  render  it  more  pleasant.  There  are 
several  varieties  manufactured  ;  the  degree  of  hardness 
of  each  is  due  to  the  quantity  of  stearin  and  chalk  in- 
corporated with  the  gum. 

This  material  has  of  late  years  largely  superseded  the 
use  of  beeswax  for  impressions,  on  account  of  its  taking 
a  somewhat  sharper  impression  and  being  more  elastic. 
It  has  also  many  more  desirable  properties  than  gutta- 
percha, which  was  formerly  used  extensively,  but  is  now 


20  DENTAL    PROSTHESIS    AND    METALLURGY. 

employed  to  such  a  limited  extent  that  it  will  not  be 
considered  in  this  work. 

Beeswax. — Beeswax  is  a  solid,  concrete  animal 
product,  prepared  by  the  honey  bees,  and  is  extracted 
from  the  comb  after  the  honey  has  been  removed. 
There  are  two  varieties  of  this  wax  in  common  use,  the 
white  and  yellow.  When  first  obtained  from  the  comb 
it  is  of  a  bright  yellow  color,  and  in  order  to  bleach  it 
and  obtain  what  is  known  as  white  wax  it  is  reduced  to 
thin  cakes  and  exposed  for  a  long  time  to  the  sun  in  the 
open  air ;  this  renders  it  less  tenacious,  but  it  is  pre- 
ferred by  some  on  account  of  its  color. 


METHODS    OF   TAKING    IMPRESSIONS 
OF  THE   MOUTH. 

Impressions  in  Plaster. — Before  mixing  the  plas- 
ter a  suitable  impression  tray  or  cup  should  be  selected. 
In  determining  this  the  cup  should  be  tried  in  the 
mouth,  and  if  exactly  adapted  to  the  case  proceed  as 
follows : — 

For  full  upper  impressions  place  a  piece  of  sof- 
tened beeswax  across  the  rear  of  the  palatine  portion  of 
the  cup  (Fig.  5  shows  the  form  of  cup  to  be  used)  just 
sufficient  to  support  the  plaster  at  that  point,  making  it 
more  certain  to  secure  a  correct  impression  of  the  pal- 
ate, especially  where  the  arch  is  very  high.  It  also  aids 
in  keeping  the  plaster  from  being  forced  over  the  rear 
of  the  cup  into  the  fauces.     If  the  tuberosities  are  deep 


METHODS    OF    TAKING    IMPRESSIONS. 


21 


a  little  wax  should  be  placed  around  the  posterior  cor- 
ners of  the  cup,  and  when  the  alveolar  ridge  is  unusually 
deep,  and  it  is  desirable  to  obtain  a  high  impression 
over  the  region  of  the  cuspids,  place  a  layer  of  wax 
over  the  edge  of  the  cup  at  these  points  also,  before 
mixing  the  plaster. 

Method  of  Mixing  Plaster. — The  best  method 

Fig.  5. 


is  that  which  most  perfectly  excludes  the  air,  prevents 
expansion,  and  gives  the  sharpest  and  smoothest  impres- 
sion or  cast.  (1)  A  medium-sized  bowl  (rubber  is  the 
most  convenient)  should  be  partially  filled  with  water 
(warm  water  is  pleasanter  for  the  patient  and  hastens 
the  setting  of  the  plaster) ;  to  this  should  be  added 
about  ten  grains  of  common  salt,  to  hasten  the  setting 
and  to  make  the  plaster  more  brittle.     It  is  better  to 


2  2  DENTAL   PROSTHESIS   AND    METALLURGY. 

add  the  salt  at  this  time,  that  is,  before  adding  the  plas- 
ter, as  it  gives  it  a  better  opportunity  to  become  uni- 
formly diffused.  Other  agents,  such  as  chlorate  of  pot- 
ash, potassium  sulphate,  and  alum,  have  been  and  are 
used  to  hasten  the  setting  of  plaster,  but  salt  is  the  least 
objectionable  and  answers  every  purpose.  (2)  The 
plaster  should  then  be  sprinkled  into  the  water  by 
tapping  the  spatula  on  the  edge  of  the  bowl;  this  will 
allow  the  air  which  is  always  found  in  plaster  to  es- 
cape before  the  plaster  sinks.  This  sprinkling  process 
should  be  continued  until  all  the  water  is  taken  up; 
or  when  a  sufficient  quantity  for  the  case  in  hand  has 
been  added,  pour  off  the  surplus  water,  then  add  what 
plaster  can  be  conveniently  carried  on  the  spatula. 
This  will  usually  give  the  proper  consistency  for  taking 
impressions,  that  is,  just  thick  enough  not  to  run  off  an 
inverted  impression  cup  or  the  spatula.  (3)  The  mix- 
ture should  then  be  quickly  and  thoroughly  stirred  for 
about  ten  seconds,  so  that  every  particle  of  plaster  has 
an  opportunity  to  absorb  the  proper  amount  of  water. 

After  the  plaster  has  been  prepared  and  mixed  as 
directed,  fill  the  cup  about  level  full,  not  more  unless 
the  palate  or  arch  is  unusually  high,  in  which  case  place 
a  little  more  over  the  wax  at  this  point.  Stand  at  the 
right  side  of  the  chair,  and  direct  the  patient  to  sit 
erect ;  then  pass  the  left  hand  around  the  patient's  head 
and  distend  the  lips  so  as  to  allow  the  cup  with  the 
plaster  to  pass  in  freely,  carefully  pressing  the  rear  of 
the  cup  in  place ;  afterward  bring  it  up  firmly  in  front. 
This  will  force  any  excess  of  plaster  forward.     Now,  by 


METHODS    OF    TAKING    IMPRESSIONS.  23 

having  the  first  two  fingers  of  each  hand  support  the 
cup  under  the  center  of  the  alveolar  ridge,  the  pressure 
will  be  equally  distributed,  and  the  thumbs  will  be  free 
to  press  the  lip  in  and  up  so  as  to  force  the  plaster  well 
up  over  the  alveolar  ridge. 

If  there  is  retching  (tendency  to  vomit),  incline 
the  patient's  head  a  little  further  forward  and  direct  him 
to  resist  the  tendency,  to  keep  the  tongue  and  throat 
quiet,  and  breathe  entirely  through  the  nose. 

If  the  line  of  wax  has  been  placed  across  the  heel  of 
the  impression  cup,  and  the  directions  carried  out,  it  is 
the  impression  of  the  author  that  further  treatment  need 
seldom  be  resorted  to.  There  are  rare  instances,  how- 
ever,— some  cases  of  cleft  palate,  for  example, — where 
the  soft  palate  is  so  extremely  sensitive  that  it  will  not 
permit  sufficient  contact  without  some  local  or  constitu- 
tional treatment.* 

Tests  for  Perfect  Impression. — The  most  relia- 
ble test  for  a  perfect  impression  is  the  degree  of  resist- 
ance to  its  removal.  The  time  for  removal  can  be 
ascertained  by  breaking  a  small  piece  of  the  plaster 
from  the  surplus  in  front ;  if  there  is  a  clean,  sharp 
break  the  impression  should  be  promptly  removed. 

*  As  a  constitutional  remedy,  bromid  of  potassium  is  probably 
the  best;  give  10  grains  before  retiring,  20  grains  the  following 
morning,  and  20  grains  additional  in  a  few  hours;  one  hour  after 
which  take  impression.  Local  treatment  consists  in  making  appli- 
cation of  cocain  or  manipulating  the  parts  with  a  feather  or  edge  of 
a  napkin,  or  in  gargling  the  throat  with  camphor  water  just  before 
taking  impression. 


24  DENTAL   PROSTHESIS   AND    METALLURGY. 

Manner  of  Removing  Impression. — The  resist- 
ance which  results  from  the  exclusion  of  the  air  from 
between  the  plaster  and  the  mucous  membrane  of  the 
palate  should  be  considerable  where  a  perfect  impres- 
sion has  been  secured.  This  is  best  overcome  by  rais- 
ing the  lip  and  cheek  on  the  sides  and  in  front,  allowing 
the  air  to  pass  in  over  the  rim  of  the  cup ;  this  will 
usually  allow  it  to  be  readily  removed.  Should  there 
be  further  difficulty,  however,  the  air  may  be  admitted 
by  pressing  up  the  soft  palate  at  the  rear  of  the  cup ; 
or  the  patient  may  be  directed  to  give  a  slight  cough ; 
this  will  raise  the  soft  palate  and  admit  the  air  between 
it  and  the  impression,  allowing  it  to  be  easily  taken  out. 

For  Full  Lower  Impression. — A  cup  of  suitable 
shape  (see  Fig.  6)  and  size  should  be  selected,  and  modi- 
fied with  a  rim  of  wax  to  suit  the  case  in  hand ;  it  is  also 
advisable,  especially  where  a  new  or  very  smooth  cup  is 
to  be  used,  and  where  the  mouth  presents  a  decided 
undercut,  to  place  a  film  of  wax  over  ks  surface  to  pre- 
vent the  plaster  leaving  it. 

Fill  the  cup  with  plaster,  prepared  as  before,  then 
step  to  the  right  side  and  a  little  in  front  of  the  chair, 
facing  the  patient,  so  that  you  can  more  readily  see  to 
place  the  cup  in  the  proper  position.  Distend  the  left 
corner  of  the  mouth  and  the  cheek  with  the  side  of  the 
impression  cup  as  it  is  being  passed  into  the  mouth,  and 
the  right  at  the  same  time  with  the  left  hand,  and  adjust 
the  cup  to  the  ridge,  that  is,  place  it  so  that  the  center 
of  the  cup  will  come  directly  over  the  top  of  the  ridge. 

Now  step  back  quickly  to  the  position  taken  for  upper 


METHODS    OF   TAKING    IMPRESSIONS. 


25 


impressions,  and  pass  the  left  hand  back  of  and  around 
the  patient's  head ;  press  the  cheeks  away  from  the  cup 
when  necessary,  so  there  will  not  be  a  fold  of  membrane 
underneath;  then  with  the  thumbs,  one  on  either  side 
over  the  center  of  the  ridge,  press  the  cup  down  care- 
fully but  firmly  into  position.  At  the  same  time  direct 
the  patient  to  thrust  the  tongue  upward  and  forward. 
In  this  way  an  impression  of  that  portion  of  the  mylo- 

Fig.  6. 


hyoid  muscle  and  the  cord  (fraenum  linguae)  which  is 
attached  to  the  ridge  just  beneath  the  tip  of  the  tongue, 
is  secured,  while  they  are  elevated  and  tense ;  they 
will  then  not  disturb  the  plate  while  they  are  in  motion, 
as  in  speech  and  mastication.  It  will  sometimes  be 
found  that  a  perfect  lower  impression  will  offer  consid- 
erable resistance  to  removal,  on  account  of  the  adhe- 
sion and  undercuts.      Where  this  is  the  case,  air  can 


26 


DENTAL    PROSTHESIS    AND    METALLURGY. 


readily  be   admitted   by   drawing   away  the   lips   and 
cheeks. 

For  partial  impressions,  cups  of  a  different  pat- 
tern are  required.  Fig.  7,  a,  I?,  c,  shows  the  general 
form  of  cups  used  for  such  a  purpose.  Many  partial 
impressions  can  be  readily  taken  by  simply  preparing 
the  cups  as  directed  for  full  impressions.  The  simplest 
method  is  to  first  take  an  impression  in  wax  and  then 


Fig.  7. 


a. 


remove  a  layer  from  its  surface,  that  is,  from  the  surface 
representing  that  portion  of  the  mouth  or  ridge  where 
the  plate  and  teeth  are  to  rest ;  place  sufficient  plaster  at 
these  points  to  replace  this  layer  of  wax,  and  carefully 
return  it  to  the  mouth. 

In  taking  partial  impressions  it  is  important  that  the 
surface  of  the  wax  should  be  roughened  by  cutting 
grooves,  so  that  the  plaster  will  be  thoroughly  anchored 


METHODS    OK   TAKING    IMPRESSIONS. 


27 


to  the  cup.     It  is  also  important,  when  a  layer  of  wax 
is  removed,  especially  in  the  interdental  spaces  where 


c. 


the  teeth  are  to  go,  that  it  be  of  considerable  thickness, 
so  that  the  plaster,  should  it  break,  will  have  sufficient 
strength  to  allow  of  accurate  replacement.     Again,  it  is 


28  DENTAL   PROSTHESIS    AND    METALLURGY. 

important  that  the  plaster  should  not  set  as  hard  as  in 
full  cases,  so  that  the  impression  will  not  adhere  to  the 
mouth  and  have  to  be  broken  away  in  pieces ;  this  can 
usually  be  avoided  by  a  little  care. 

Manner  of  Obtaining  Impression  in  Wax  or 
Compound. — The  first  step,  of  course,  is  to  select  a 
properly  shaped  cup  for  the  case  in  hand ;  then  look  to 
the  secretions  of  the  mouth.  If  the  secretions  are 
abundant,  thick,  or  viscid,  they  should  be  removed  by 
rinsing  the  mouth  with  salt  and  water.  The  impression 
material,  whether  wax  or  compound,  may  then  be  soft- 
ened by  gently  heating  over  a  lamp  or  Bunsen  burner, 
or,  as  some  prefer,  by  immersing  in  hot  water ;  when 
the  latter  method  is  employed  the  moisture  should 
always  be  absorbed  from  the  surface  with  a  towel  or 
napkin  before  manipulating  with  the  hands. 

The  cup  should  then  be  filled  with  the  softened  mate- 
rial and  impression  taken.  The  position  of  both  patient 
and  operator,  and  the  manner  of  introducing  the  cup 
into  the  mouth  is  the  same  as  has  been  directed  for  tak- 
ing impressions  in  plaster.  But  it  must  be  remembered 
that  these  materials  will  not  flow  as  plaster  does,  so  it  is 
very  necessary  that  firm  and  steady  pressure  should  be 
used  against  the  cup  in  order  to  secure  a  good  impres- 
sion of  every  desirable  part,  and  to  aid  in  this  the 
patient  should  be  directed  to  draw  down  the  lip,  and 
the  impression  material  should  be  pressed  in  all  around 
above  the  rim,  the  pressure  on  the  surface  of  the  cup 
must  at  the  same  time  be  kept  firm  and  steady.  The 
hardening  of  these  materials  may  be  hastened  by  dip- 


METHODS    OF    TAKING    IMPRESSIONS.  29 

I 

ping  the  corner  of  a  napkin  or  a  piece  of  cotton  in  cold 
water,  and  passing  it  over  the  surface  of  the  cup.  When 
it  is  firm  enough  to  remove  it  must  be  done  with  great 
care,  and  the  direction  of  its  removal  must  be  deter- 
mined by  the  position  of  any  remaining  teeth,  or  the 
projection  of  the  ridge.  And  though  much  care  is 
taken  the  impression  is  never  as  sharp  as  where  plaster 
is  used,  and  there  exists  such  a  probability  of  imperfec- 
tion from  bending  or  dragging  due  to  undercuts,  that 
plaster  should  be  the  material  used  in  all  cases  possible, 
the  more  difficult  the  case  the  more  reason  why  it  should 
be  employed. 

Preparing  the  Vacuum  Chamber. — In  full  cases 
it  is  not  necessary,  as  a  rule,  to  make  a  vacuum  cham- 
ber in  the  plate.  All  that  is  required  to  secure  suffi- 
cient adhesion  is  to  have  the  plate  come  in  close  contact 
with  the  palate  and  ridge  at  every  point,  that  is  to 
have  the  pressure  equally  distributed.  (See  carving  of 
models.) 

In  partial  cases  or  where  for  any  reason  it  is  desired 
to  use  a  vacuum  chamber,  the  simplest  and  one  of  the 
best  methods  is  to  cut  the  form  of  the  chamber  in  the 
impression  before  using  the  varnish.  The  plaster  in 
this  way  will  be  raised  at  a  corresponding  point  upon 
the  cast,  and  will  have  the  same  form  and  depth  as  the 
cavity  cut  in  the  impression.  Should  it,  however,  be 
desirable  to  change  the  general  shape  of  the  chamber, 
this  raised  portion  can  readily  be  carved  to  the  desired 
shape  and  size.  With  this  form  of  vacuum  chamber 
there  is  no  danger  of  displacement  or  having  holes  in 


3<D  DENTAL    PROSTHESIS    AND    METALLURGY. 

the  plate  by  the  loosening  and  dropping  of  pins  used  to 
attach  the  metal  chamber  forms  to  the  cast. 


PLASTER  MODELS  OR  CASTS. 

After  securing  a  perfect  impression  of  the  mouth,  the 
next  important  step  in  the  construction  of  an  artificial 
denture  is  to  obtain  from  the  impression  a  correct 
representation  of  the  parts  in  plaster.  This  counterpart 
or  copy  is  called  a  model  or  cast. 

Manner  of  Obtaining  Casts. — When  preparing 
a  cast  from  a  wax  or  modeling  compound  impression, 
it  is  not  necessary  to  coat  impression  with  any  separat- 
ing material  excepting  to  dip  them  in  water  just  before 
pouring  the  plaster,  as  water  is  more  easily  displaced  than 
air.  Mix  plaster  as  for  taking  impressions,  excepting 
that  it  should  be  a  little  thinner  and  that  nothing  is 
needed  to  hasten  the  setting.  In  partial  cases  it  is  often 
desirable  to  strengthen  the  plaster  teeth  to  secure  them 
against  accident  in  handling,  especially  such  as  are  to 
be  used  in  adjusting  clasps,  and  those  adjoining  the 
space  to  be  filled  by  the  artificial  teeth.  This  support 
may  be  given  by  placing  short  pieces  of  stiff  wire  or 
ordinary  pins  vertically  in  the  depressions  made  in  the 
impression  by  the  teeth,  and  in  order  to  support  them 
in  this  upright  position  until  the  plaster  is  poured,  the 
end  of  each  pin  should  be  slightly  forced  or  imbedded 
in  the  impression  material  in  the  center  of  the  bottom 
of  each  cavity.     The  plaster  should  then  be  mixed  and 


PLASTER   MODELS    OR    CASTS.  3 1 

poured ;  in  doing  so  it  should  not  be  poured  directly 
into  the  cavity  formed  by  the  teeth,  but  a  little  of  the 
plaster  should  be  placed  at  a  point  just  back  of  these 
cavities,  and  then  gently  but  hastily  coaxed  into  them 
by  slightly  tapping  the  bottom  of  the  impression  cup 
against  the  table.  In  this  way  the  air  and  water  are 
expelled  and  the  plaster  more  perfectly  fills  the  cavities, 
which  of  course  will  give  more  perfectly  shaped  teeth 
on  the  cast,  that  is  they  will  be  minus  the  "  air  bubbles" 
so  often  seen  in  such  cases.  Sufficient  plaster  should 
then  be  added  to  give  to  the  model  a  depth  of  about  two 
inches. 

To  Separate  Cast  from  the  Impression. — They 
should  be  immersed  in  warm  water  until  the  impression 
material  is  sufficiently  soft  to  allow  of  its  being  readily 
removed.  Or  dry  heat  may  be  applied  to  the  impres- 
sion until  the  same  result  is  accomplished. 

To  Obtain  Cast  From  Plaster  Impression. — 
The  manipulation  required  in  securing  a  model  from  a 
plaster  impression  is  much  the  same  as  when  wax  or 
modeling  compound  has  been  used,  though  there  are 
a  few  details  which  are  very  essential.  There  are  vari- 
ous methods  of  preparing  the  impression,  but  in  this, 
as  in  every  subject  treated,  our  endeavor  is  to  give  the 
correct  way ;  by  that  we  mean  the  method  which  has 
proven  the  most  satisfactory,  not  only  in  our  own  hands, 
but  to  many  of  the  most  progressive  practitioners  and 
teachers. 

Separating  Fluids. — Of  the  materials  used  for 
separating,  probably  the  best  are  shellac  varnish,  and 


32  DENTAL    PROSTHESIS    AND    METALLURGY. 

soapy  water.  The  shellac  is  not  a  parting  fluid,  but 
is  used  simply  to  stain  the  plaster,  so  that  the  line  of 
demarkation  between  the  impression  and  cast  will  be 
more  clearly  indicated.  After  this  has  thoroughly  dried 
the  impression  should  be  coated,  by  means  of  a  camel's 
hair  brush,  with  the  soapy  solution,  which  gives  it  a 
smooth,  glossy  surface,  ensuring  easy  separation.  Care 
must  be  taken,  however,  to  leave  none  of  this  solution 
unabsorbed  on  the  impression  or  in  the  imprints  of  the 
teeth,  or  the  face  of  the  cast  will  not  be  as  sharp  and 
smooth  as  is  desirable.  This  is  best  removed  by  wash- 
ing the  surface  off  thoroughly,  when  the  impression 
will  be  ready  to  receive  the  plaster  for  the  model. 

The  same  measures  for  mixing  and  pouring  cast  and 
for  strengthening  the  plaster  teeth  should  then  be  pur- 
sued as  directed  where  wax  or  modeling  compound  has 
been  used. 

A  very  simple  though  effective  method  of  staining 
the  plaster  is  to  color  the  water  used  in  mixing  the 
plaster  for  the  impression  with  anilin  red  or  rose  pink. 
The  latter  gives  the  plaster  such  a  delicate  pink  color 
that  it  is  quite  unobjectionable  to  the  patient,  and  at  the 
same  time  the  coloring  is  sufficient,  so  that  the  impres- 
sion can  be  readily  distinguished  from  the  cast  in 
separating.  When  this  is  used  the  shellac  varnish,  of 
course,  is  not  necessary. 

The  objections  to  oil  are  that  plaster  will  not 
flow  smoothly  over  an  oiled  surface,  and  that  it  has  a 
tendency  to  soften  the  surface  of  the  cast. 

Separation. — The   manner   of  separation   is   more 


PLASTER   MODELS    OR    CASTS. 


33 


difficult  where  plaster  has  been  used  for  the  impression 
material,  and  requires  more  care.  It  is  needless  to  say 
that  one  good  cast  is  better  than  several  poor  ones,  so 
every  care  should  be  taken  in  separating,  and  no  effort 
should  be  made  to  save  the  impression  for  further  use,  as  it 
would  usually  be  at  the  expense  of  the  cast  should  we 
do   so.     There   are    cases,  however,    both    upper   and 


Fig.  8. 


lower,  where  the  mouth  is  so  flat  that  they  can  be  read- 
ily separated,  either  by  taking  the  model  in  the  hand 
and  tapping  the  handle  of  the  cup,  or  by  slipping  a 
wedge-shaped  instrument  between  the  impression  and 
cast  at  its  posterior  border. 

We  usually  find  more  or  less  under  cuts,  and  often  the 
ridge  is  thin  and  prominent,  or  we  may  have  a  number 
of  teeth  remaining.     In  all  these  cases,  and  they  repre- 


34  DENTAL   PROSTHESIS   AND    METALLURGY. 

sent  more  than  the  majority,  the  impression  can  only 
be  removed  with  safety,  that  is,  so  as  not  to  deface  the 
model,  by  being  carefully  broken  away  piece  by  piece. 
The  rim  of  plaster  on  the  outer  side  of  the  ridge  is  first 
removed ;  this  is  best  accomplished  by  removing  the 
cup  from  the  impression,  and  then  cut  a  groove  around 
the  latter  al  a  point  directly  over  the  ridge,  as  deeply 
as  possible  without  marring  the  face  of  the  cast,  then 
begin  at  one  corner  and  break  away  the  rim  piece  by 
piece,  after  which  the  palatine  portion  can  be  readily 
removed.  Fig.  8  indicates  where  grooves  should  be  cut 
so  that  the  impression  may  easily  be  removed  from  the 
cast.  When  it  is  desired  to  prepare  a  model  for  permanent 
preservation,  it  should  be  thoroughly  dried  and  then  im- 
mersed for  a  short  time  in  a  solution  of  carbonate  of  soda ; 
the  surface  will  then  be  converted  into  carbonate  of  lime, 
which  will  render  it  hard  and  durable.  Or  the  model 
may  be  boiled  in  a  strong  solution  of  alum.  Or  add  to 
the  plaster  from  five  to  six  per  cent,  of  powdered  alum, 
or  the  same  amount  of  ammonium  chlorid,  before 
mixing  with  water. 

To  retard  the  setting  of  plaster,  mix  with  it  before 
adding  the  water,  about  three  per  cent,  of  powdered 
althaea  root.  But  where  for  any  reason  it  is  desirable 
to  retard  the  setting  for  a  half  hour  or  longer,  about 
eight  per  cent,  of  althaea  root  should  be  added.  This 
not  only  retards  the  setting  of  the  plaster  but  enables 
it  to  be  sawed,  filed  or  turned. 

The  Separating  Fluids  are  very  easily  made 
and  are   inexpensive.     For  the  soap   solution  take   of 


PLASTER   MODELS    OR    CASTS. 


35 


castile  soap  one  ounce,  and  dissolve  in  a  pint  of  hot 
water.  This  solution  should  then  be  kept  bottled.  In 
preparing  the  shellac  varnish,  take  of  pure  gum  shellac 
one  ounce  and  alcohol  about  a  half  pint ;  this  should 
be  digested  over  a  moderate  heat  until  thoroughly  dis- 
solved, when  it  should  be  kept  securely  bottled. 

One   of  the  most   convenient  methods   for  keeping 
such  a  solution  free  from  dust  and  other  foreign  sub- 

Fig.  9. 


stances,  and  at  the  same  time  keep  it  air-tight,  so  that 
the  preparation  will  not  become  too  thick  by  evapora- 
tion of  the  alcohol,  is  to  use  the  preparation  cup  known 
as  the  "  clover  leaf,"  which  is  shown  in  Fig.  9. 

Taking  the  Bite  and  Antagonizing  the 
Models. — A  correct  articulation  is  of  as  great  import- 
ance as  any  other  feature  in  the  construction  of  an  arti- 
ficial denture,  for  no  matter  how  perfect  the  impression 
and  model,  or  how  thoroughly  and  artistically  the  plate 


36  DENTAL    PROSTHESIS   AND    METALLURGY. 

may  be  finished,  if  the  articulation  is  not  correct  the 
entire  piece  of  work  is  practically  a  failure.  It  is  in 
taking  the  bite  for  full  cases,  that  is,  for  full  upper  or 
lower,  or  both,  that  the  greatest  care  is  required.  By 
the  term  "bite,"  in  relation  to  our  subject,  is  meant 
the  relative  position  of  the  jaws  with  the  articulation  of 
the  natural  teeth,  when  there  are  any  remaining,  with 
the  length  and  contour  of  the  lips. 

For  Full  Cases. — Whether  upper  or  lower,  or  both, 
a  base  plate  of  some  firm  material,  as  paraffin  wax  or  a 
thin  sheet  of  modeling  compound,  should  be  accurately 
fitted  on  the  model,  and  the  edges  trimmed  to  the  plate 
line,  that  is,  so  as  to  clear  the  facial  or  lingual  muscles 
or  any  heavy  folds  of  mucous  membrane.  If  it  is  a 
lower  case,  whether  full  or  partial  (but  giving  greater 
assistance  in  partial  cases),  a  semicircle  of  stiff  wire, 
No.  15  or  16  standard  gauge,  should  be  imbedded  in 
the  base-plate  to  give  it  additional  strength  for  taking 
the  bite  and  trying  the  teeth  in  the  mouth.  Attach  to 
this  base-plate,  by  means  of  a  hot  spatula,  a  rim  of 
softened  beeswax,  sufficient  to  represent  (as  near  as  you 
can  judge)  a  little  more  than  the  length  and  the  fullness 
of  the  teeth  to  be  inserted.  Place  this  trial  plate  with 
rim  in  the  mouth.  Note  where  the  wax  rim  is  too  full 
or  too  long,  or  vice  versa  ;  then  remove  it,  and  trim  or 
build  up  as  the  case  may  require,  until  the  proper 
length,  fullness,  and  contour  are  attained.  As  this  wax 
is  to  be  trimmed  to  the  exact  length  that  we  wish  the 
artificial  teeth  to  be,  it  is  important  to  know  at  this 
time  that  the  upper  anterior  teeth  should  be  made  about 


PLASTER   MODELS    OR    CASTS.  37 

a  line  longer  than  the  upper  lip,  while  the  lower  are 
that  much  shorter  than  the  lower  lip.  If  it  is  a  single 
case,  whether  upper  or  lower,  the  wax  plate  should  now 
be  removed  and  the  articulating  border  passed  over  the 
flame  a  few  times  to  soften  it  sufficiently  to  readily 
receive  the  imprint  of  the  antagonizing  teeth.  It  should 
now  be  replaced  in  the  mouth  and  the  patient  directed 
to  close  the  teeth  gently  and  lightly  against  it ;  note 
carefully  the  points  of  contact,  and  have  it  repeated  by 
now  directing  the  patient  to  close  upon  the  wax  in  the 
back  part  of  the  mouth,  and  to  swallow  at  the  same 
time.  This  last  act  will  usually  force  the  teeth  into  the 
wax  sufficiently  to  imbed  the  cusps  and  cutting  edges. 
If  there  is  no  variation  in  the  points  of  articulation,  it 
is  safe  to  assume  that  the  bite  is  correct.  The  depth 
to  which  the  cutting  edges  of  the  teeth  should  be 
imbedded  in  the  wax  must  correspond  to  the  length  of 
the  "over-bite"  of  the  anterior  upper  teeth.  Now 
mark  the  median  line  on  the  wax  rim.  This  cannot  be 
safely  regulated  by  the  center  of  the  lower  teeth  or  by 
the  frenum,  as  either  may  be  a  little  to  one  side  or  the 
other,  but  should  be  determined  by  the  face  alone.  A 
line  should  be  drawn  across  the  wax  to  correspond  as 
near  as  possible  with  the  center  of  the  features. 

A  wax  or  compound  impression  of  the  antagonizing 
teeth  should  be  taken  and  the  cast  from  this  should  be 
placed  in  position,  so  that  the  cusps  and  cutting  edges 
of  the  plaster  teeth  may  be  gently  forced  into  the 
depressions  made  in  the  wax  rim  by  the  natural  teeth. 
The  two  casts  with  the  bite  held  accurately  in  position 


3« 


DENTAL   PROSTHESIS   AND    METALLURGY. 


should  now  be  securely  attached  to  the  articulator,  with 
plaster-of-Paris.     Fig.  10  represents  such  a  case. 

Where  the  bite  for  both  upper  and  lower  is  to  be 
secured,  the  base  plates  and  the  wax  rims  should  be 
prepared  as  before  directed.  Place  the  plates  in  the 
mouth,  the  lower  first ;  the  proper  length  and  contour 
should   now   be   secured   and    the   occluding    surfaces 

Fig.  io. 


trimmed,  so  that  they  will  touch  evenly  and  at  the  same 
time  upon  both  sides  of  the  mouth,  and  the  patient 
directed  to  close  lightly  upon  the  wax  in  the  back  part 
of  the  mouth.  The  median  line  should  then  be  drawn 
across  both  plates  and  a  cross,  or  two  or  three  oblique 
lines  made  on  either  side ;  after  this  is  accomplished, 
direct  the  patient  to  open  and  again  close  the  mouth ; 


PLASTER    MODELS    OR    CASTS. 


39 


note  whether  these  lines  are  brought  accurately  together  ; 
if  so,  have  the  patient  bring  slight  pressure  upon  them 
by  closing  the  jaws  a  little  harder,  when,  if  the  occluding 
surfaces  have  been  previously  passed  over  the  flame, 
they  will  adhere  so  firmly  that  they  may  be  readily 
removed  from  the  mouth  together,  without  displacement. 
Fig.  n  illustrates  them  as  removed  from  the  mouth. 

Fig.  ii. 


The  plaster  casts  should  then  be  carefully  adjusted  to 
these  wax  contour  models,  and  attached  while  in  this 
position  to  an  articulator.  By  this  means  the  plaster 
casts  will  be  placed  and  retained  in  the  relative  position 
of  the  jaws.  This  result  is  shown  in  Fig.  12,  with  the 
wax  base  plates  and  bite  removed. 

For  Partial  Cases. — When  a  large  partial  case  is 
presented,  the  base  plate  should  be  prepared  to  fit  the 


4o 


DENTAL   PROSTHESIS    AND    METALLURGY. 


cast ;  then  a  small  piece  of  softened  wax  should  be 
adjusted  in  the  spaces  that  are  to  be  supplied  with  teeth. 
This  should  be  placed  in  the  mouth  and  the  patient 
directed  to  bring  the  teeth  carefully  together  ;  if  this 
has  been  correctly  done,  the  bite  should  be  removed 
and  replaced  upon  the  plaster  cast.  Then  a  wax  or 
compound  impression  of  the  opposing  teeth  should  be 

Fig. 12. 


taken,  and  from  this  a  plaster  cast  secured  which  artic- 
ulates with  the  cast  containing  the  base  plate  and  bite. 
The  two  casts  should  then  be  carefully  secured  in  the 
articulator. 

Where  only  one  or  two  teeth  are  missing  in  the  same 
locality,  it  is  not  necessary,  as  a  rule,  to  take  the  bite  in 
this  manner.     All  that  is  usually  required  is  to  secure  a 


PLASTER    MODELS    OR    CASTS.  4 1 

cast  of  the  opposing  teeth,  and  an  observing  eye  to  note 
the  peculiarities  of  the  case  and  to  aid  you  in  adjusting 
the  casts  so  that  the  occluding  surfaces  will  correspond 
exactly  with  the  articulation  of  the  natural  teeth.  But 
where  the  number  of  teeth  missing  is  so  great,  or  where 
for  any  reason  there  is  any  doubt  as  to  being  able  to 
articulate  the  casts  in  this  way,  and  where  the  cast  is 
not  sufficiently  large  to  require  a  base-plate,  etc.,  a  very 
simple  method  is  to  take  a  small  roll  of  softened  wax 
an  inch  or  more  long,  according  to  the  number  of  teeth 
lost,  place  this  wax  between  the  remaining  teeth,  press- 
ing against  the  teeth  on  either  side  of  the  space,  and 
direct  the  patient  to  close  the  teeth  naturally,  that  is,  to 
bite  into  the  wax  until  the  cutting  edges  and  cusps  are 
brought  firmly  and  accurately  together.  The  wax 
should  now  be  pressed  firmly  against  the  ridge  where 
the  teeth  are  to  be  replaced,  and  against  the  outer,  that 
is,  the  labial  or  buccal,  surface  of  the  antagonizing  teeth. 
This  bite  should  now  be  removed  from  the  mouth  and 
placed  for  a  moment  in  cold  water.  With  this  guide 
the  casts  may  now  be  nicely  adjusted  in  the  articulator. 
Carving  the  Model. — In  order  to  secure  a  close 
adaptation  of  the  plate  at  every  point — which  is  neces- 
sary to  secure  perfect  adhesion  between  the  denture  and 
the  mucous  membrane  of  the  palate — the  cast  or  model 
should  be  so  carved  that  the  pressure  will  be  equally  dis- 
tributed. Before  dismissing  the  patient  after  taking  the 
bite,  the  mouth  should  again  be  closely  examined,  and 
the  cast  scraped  or  carved  where  additional  pressure  will 
be  required  ;  that  is,  wherever  the  tissues  of  the  palate 
4 


42  DENTAL   PROSTHESIS    AND    METALLURGY. 

are  found  to  be  softer  and  more  yielding  than  at  other 
points.  For  instance,  take  a  case  that  is  not  unusual, 
where  a  prominent,  hard  ridge  is  found  in  the  center  of 
the  palate.  Here  it  would  be  necessary  to  carve  away 
considerable  of  the  plaster  on  either  side  where  the 
tissues  are  softer  in  order  to  equalize  the  pressure,  or  the 
finished  denture  would  rock  upon  the  hard  point  and 
thus  practically  prove  a  failure.  In  nearly  all  cases  a 
little  carving  at  the  posterior  edge,  from  the  plate  line 
forward,  will  prove  advantageous,  and  in  some  cases  a 
groove  should  be  cut  around  the  outside  of  the  ridge 
where  the  parts  are  yielding,  which  will  form  a  raised 
line  or  "  bead  "  on  the  plate  just  under  the  margin  of 
the  rim.  Also  when  plain  teeth  are  to  be  placed  directly 
upon  the  gums,  as  shown  in  Fig.  21,  the  cast  should  be 
carved  at  the  points  where  the  teeth  are  to  rest,  so  that 
they  will  set  firmly  upon  the  natural  gum  when  the  den- 
ture is  completed. 

The  shade  of  the  teeth  should  also  be  taken  at  this 
visit ;  this,  of  course,  should  be  to  match  the  natural 
teeth — where  any  remain — as  accurately  as  possible  ; 
but  where  all  are  missing,  a  tooth  most  suitable  in 
shape,  size,  and  color  should  be  selected.  This,  how- 
ever, will  be  more  fully  dwelt  upon  in  the  following 
chapter. 


SELECTION    AND    ARRANGEMENT   OF   TEETH.  43 

THE  SELECTION  AND  ARRANGE- 
MENT OF  THE  TEETH. 

THE     ESTHETIC     AND      PHYSIOGNOMICAL     RE- 
QUIREMENTS. 

In  making  up  the  facial  features,  the  jaws  and  teeth 
form  a  very  important  part.  The  teeth,  standing,  as  they 
do,  as  guards  about  the  entrance  to  the  digestive  tract, 
tell  to  the  thoughtful  student — by  their  size,  form,  color, 
texture,  and  relative  position — not  only  of  the  physi- 
ological condition  of  the  individual,  but  of  the  mental 
and  moral  power  or  weakness.  To  replace  these  organs, 
then,  with  fidelity  will  require  broad  art  culture  and  the 
highest  order  of  intelligent  discrimination. 

This  is  most  excellently  expressed  by  the  late  Dr. 
James  W.  White,  who  was  one  of  the  most  intelligent 
contributors  to  the  literature  of  dental  art,  where 
he  says :  "  No  matter  how  anatomically  correct,  or  how 
skilfully  adapted  for  speech  and  mastication,  an  arti- 
ficial denture  may  be,  yet,  if  it  bear  not  the  relation 
demanded  by  age,  temperament,  facial  contour,  etc.,  it 
cannot  be  otherwise  than  that  its  artificiality  will  be 
apparent  to  every  beholder. 

"  This  law  of  correlation,  harmony,  running  through 
nature,  attracts  and  enchants  us  by  an  infinite  diversity 
of  manifestations ;  the  failure  to  recognize  its  demands 
by  art  is  correspondingly  abhorrent  to  our  sensibilities. 

"There  is  a  relation  between  the  physical  form  and 
the  voice,  from  which  we  are  led  to  infer  in  advance  the 
character  of  the  tones  which  from  any  given  individual 


44  DENTAL    PROSTHESIS   AND    METALLURGY. 

may  be  expected.  This  law  of  association,  in  any  case 
having  led  us  to  expect  a  base  voice,  the  anomaly  should 
a  falsetto  greet  us  is  almost  ludicrous. 

"  There  is  a  similar  relation  between  other  physical 
characteristics  and  the  teeth.  A  broad,  square  face,  or 
an  oval;  a  large,  coarse-featured  man,  or  a  delicately- 
organized  woman  ;  a  miss  of  eighteen  or  a  matron  of 
fifty ;  a  brunette  or  a  blonde, — these  and  other  varieties 
present  as  many  different  types,  with  teeth,  in  size, 
shape,  color,  density,  etc.,  corresponding.  If,  then, 
teeth  correlated  in  their  characteristics  to  those  which 
nature  assigns  to  one  class  be  inserted  in  the  mouth  of 
one  whose  physical  organization  demands  a  different 
order,  the  effect  cannot  be  otherwise  than  displeasing 
to  the  eye,  whether  the  observer  be  skilled  in  perception, 
or  intuitively  recognizes  inharmony  without  understand- 
ing the  cause." 

"  Re-Posing  the  Features.* — By  the  term  re- 
posing the  features,  we  include  everything  necessary  to 
bring  each  and  all  of  the  visible  parts  of  the  face  and 
mouth  into  harmony  of  relation  to  each  other.  This 
necessarily  includes  the  teeth ;  the  relation  of  the 
lower  to  the  upper  jaw ;  the  lips,  cheeks,  and  the 
soft  parts  of  the  face  that  have  assumed  a  wrong 
position  by  the  reason  of  the  loss  of  the  natural 
organs.  After  the  teeth  have  been  selected  with 
color  and  form  adapted  to  the  individual  patient,  the 
final  position  of  the  features  becomes  the  most  impor- 

*  Through  the  courtesy  of  the  Wilmington  Dental  Manufacturing  Co. 


SELECTION    AND    ARRANGEMENT    OF    TEETH.  45 

Fig.  13. 


46  DENTAL    PROSTHESIS    AND    METALLURGY. 

tant  question.  The  visible  portions  of  the  teeth  may 
be  of  good  form,  color,  and  arrangement,  and  yet 
other  points  of  the  form  may  render  them  unfit  for 
the  case.  These  points  are  such  as  relate  to  the  place- 
ment of  the  teeth  in  the  mouth  in  such  a  position,  in 
relation  to  the  alveolar  process,  or  gums  and  lips,  cheeks 
and  tongue,  as  to  bring  the  features' into  correct  pose. 
For  this  purpose  teeth  with  long  porcelain  gum  attached 
(gum  teeth)  will  be  required  in  some,  while  in  other 
cases  plain  teeth  will  be  demanded,  as  the  space  to  be 
filled  out  to  give  the  features  the  proper  pose  be  great 
or  small.  This  relates  to  full  dentures,  and  even  to 
partial  cases.  With  the  loss  of  the  teeth  the  general 
pose  of  the  several  parts  of  the  lower  face  is  seriously 
disturbed.  The  teeth  in  occlusion  have  held  the  jaws 
at  a  certain  position  in  which  the  powerful  masseter  and 
temporal  muscles  which  close  the  mouth  are  still  capable 
of  vigorous  action.  These  muscles  are  much  stronger 
than  those  which  act  in  opening  the  mouth.  With  the  loss 
of  the  teeth  the  prop  which  stopped  the  lower  jaw  short  in 
its  motion  is  removed,  and  the  jaw  swings  beyond  its 
normal  position  a  distance  which  varies  much  in  differ- 
ent cases,  and  usually  increases  with  the  time  the  patient 
has  been  without  teeth.  The  motion  of  the  chin  is 
forward  and  upward,  as  illustrated  in  Fig.  13.  The 
condyloid  process  of  the  lower  jaw  hinges  in  to  the 
glenoid  cavity  of  the  temporal  bone  at  A.  The  line  B 
is  drawn  from  the  joint  to  the  chin,  and  the  dotted  line 
C  is  the  curve  on  which  the  lower  jaw  swings  when  in 
motion.  When  the  teeth  have  been  lost  the  lower  jaw 
is  free  to  move  farther,  and  the  line  B  swings  forward 


SELECTION   AND    ARRANGEMENT    OF   TEETH.  47 

and  upward  to  the  dotted  line  E,  carrying  the  chin  up- 
ward and  forward  toward  the  nose,  on  the  dotted  line 
C,  raising  it  a  distance  represented  by  the  horizontal 
parallel  lines  F,  and  forward  the  distance  represented 
by  the  parallel  lines  G.  The  lips  have  been  held  for- 
ward in  their  normal  pose  by  the  teeth.  With  the  loss 
of  the  teeth  they  lose  this  support  and  drop  back  to  the 
dotted  lines  /,  /.  dragging  with  them  the  surrounding 
soft  parts  and  not  infrequently  pull  down  the  point  of 
the  nose.  This  occurs  most  frequently  in  persons  who 
have  been  without  teeth  for  some  years.  With  the  loss  of 
teeth  the  tongue  undergoes  a  change  of  form.  Being 
purely  muscular,  and  capable  of  assuming  the  most 
variety  of  forms,  and  having  been  confined  upon  either 
side  by  the  teeth,  it  spreads  laterally,  as  if  in  endeavor 
to  fill  the  space.  It  soon  becomes  much  broader  than 
before,  so  that  more  of  its  bulk  comes  forward  into  the 
upper  part  of  the  oral  cavity  ;  and  the  floor  of  the 
mouth  and  submental  tissues  are  raised  at  the  point  H. 

"This,  with  the  dropping  back  of  the  lower  lips,  gives 
the  point  of  the  chin  a  peculiarly  sharp  appearance. 
The  changes  in  appearance  which  the  face  undergoes  is, 
in  some  degree,  represented  in  Fig.  14.  These  changes 
are,  however,  as  variable  as  persons,  and  it  is  our  inten- 
tion to  speak  of  the  manner  and  direction  in  which  they 
occur  rather  than  of  the  degree. 

"As  we  have  said,  this  malposition  of  the  features 
occurs  in  variable  degree,  owing  largely  to  the  position 
or  prominence  of  the  natural  teeth,  the  amount  of  shrink- 
age of  the  alveolar  process,  the  thinness  or  thickness  of 
the  lips,  etc. ;  and  the  esthetic  taste  of  the  prosthetic 


48 


DENTAL    PROSTHESIS    AND    METALLURGY. 


dentist  is  brought  to  the  test  in  the  re-posing  of  the 
features.     Teeth  may  have   been  selected  that   are  in 


Fig.    14. 


II. 


III. 


IV. 


every  way  suitable  for  the  individual  case  and  the 
symmetry  of  the  arch  itself  be  made  correct,  but  if 
they  are  not  so  placed  in  the  mouth  that  they  will  so 


SELECTION    AND    ARRANGEMENT   OF   TEETH.  49 

readjust  the  pose  of  the  parts  with  which  they  are  asso- 
ciated that  esthetic  harmony  will  be  restored,  the 
natural  expression  of  the  countenance  will  not  be 
restored.  In  this  case,  although  the  mechanical  execu- 
tion may  be  excellent,  and  the  patient  may  be  able  to 
use  the  teeth  in  mastication  and  speaking,  it  will  be  a 
failure  in  the  higher  sense  of  esthetic  prosthetic  dentis- 
try. In  order  that  there  need  be  no  failure  in  this 
direction,  the  manufacturer  is  diligently  bringing  out 
teeth  with  a  great  variety  of  and  form  of  porcelain  gum 
(gum  teeth),  including  all  needful  variety  of  gum  color, 
which  are  adapted  to  filling  out  against  the  tissues,  for  the 
purpose  of  re-posing  them  for  the  restoration  of  expres- 
sion. Also,  plain  teeth  (without  artificial  gums),  for 
use  where  much  filling  out  is  not  required.  This  gives 
the  widest  opportunity  for  selection  and  adaptation 
to  the  various  cases  presented  that  the  study  of  the  sub- 
ject has  as  yet  been  able  to  suggest.'" 

Temperamental  Indications.  —  The  completeness 
with  which  the  requirements  of  individual  cases  are 
fulfilled  depends  very  much  upon  the  ability  of  the 
dentist  to  properly  interpret  and  apply  the  basal  facts 
revealed  by  an  intelligent  study  of  the  temperaments  in 
relation  to  the  teeth. 

In  another  place,  "Temperament  in  Relation  to 
Teeth,"  Dr.  White  gives  many  appropriate  thoughts  and 
suggestions,  the  importance  of  which  justifies  our  quot- 
ing at  some  length  : — 

"The  animal  kingdom  is  divided  into  sub-kingdoms, 
classes,  orders,  families,  genera,  species.     A  further  or 


50  DENTAL    PROSTHESIS    AND    METALLURGY. 

subdivision  includes  in  minor  groups  individuals  whose 
salient  characteristics  are  correspondent  or  similar. 
Thus  every  living  creature  has  certain  physical  peculi- 
arities by  which  its  position  in  this  classification  is 
determined.  Man,  as  the  head  of  the  animal  kingdom, 
besides  having  his  place  in  this  general  scale,  is  dis- 
tinguished by  a  still  finer  classification  under  the  denomi- 
nation of  temperament — an  association  of  several  dis- 
tinguishing characteristics,  such  as  size  and  form  of 
body,  complexion,  color  of  the  eyes  and  hair,  and  to  a 
certain  extent  the  disposition  and  character  of  the 
individual. 

"Temperament  may  be  defined  as  a  constitutional 
organization,  depending  primarily  upon  heredity — 
national  or  ancestral — and  consisting  chiefly  in  a  certain 
relative  proportion  of  the  mechanical,  nutritive,  and 
nervous  systems,  and  the  relative  energy  of  the  various 
functions  of  the  body, — the  reciprocal  action  of  the 
digestive,  respiratory,  circulatory,  and  nervous  systems. 
The  stomach,  liver,  lungs,  heart,  and  brain — digestion, 
assimilation,  respiration,  circulation,  and  innervation — 
are  all  factors  in  the  differentiation  of  temperament ; 
and  according  to  the  congenital  predominance  of  one 
or  the  other,  and  the  relative  activity  of  these  functions, 
is  the  modification  of  the  characteristics  of  the  individ- 
ual which  assigns  him  to  one  or  the  other  of  the  basal 
or  mixed  temperaments.  Each  temperament  is  the 
result  as  well  as  the  indication  of  the  preponderance  of 
one  or  another  of  these  systems  and  of  relative 
functional  activity.  *         *         *         *         *         * 


SELECTION    AND   ARRANGEMENT   OF    TEETH.  5 1 

"Temperaments  are  readily  divisible  into  four  basal 
classes, — bilious,  sanguineous,  nervous,  and  lymphatic 
(see  Tables);  then  again  into  sub-classes  of  mixed  tem- 
peraments, a  combination  of  two  or  more  of  the  primary 
divisions.  In  these  combinations  one  or  other  of  the 
so-called  basal  temperaments  predominates,  and  a  com- 
pound term  is  used  to  express  the  complexity,  as,  for 
instance,  the  nervo-bilious,  signifying  that  the  bilious 
base,  the  foundation  of  temperament,  is  qualified  by  an 
admixture  of  the  nervous  element,  and  so  throughout 
the  series.  Twelve  varieties  of  temperament,  in  addi- 
tion to  the  four  basal,  may  thus  be  designated  by  the 
combination  in  pairs  of  the  original  four.  The  admix- 
ture of  the  peculiarities  of  three  or  of  all  four  of  the 
basal  temperaments  results  in  what  are  denominated 
respectively  ternary  and  quaternary  combinations, 
which  call  for  nice  discrimination  in  diagnosis;  but 
even  such  complexities  are  registered  in  the  size,  form, 
and  color  of  the  dental  organs. 

"The  value  of  a  practical  application  of  the  study  of 
temperament  in  the  practice  of  dentistry  is  apparent. 
That  the  relation  of  the  teeth  to  temperament  is,  as  a 
rule,  ignored  by  those  engaged  in  prosthetic  dentistry 
is  evident  in  the  mouths  of  a  majority  of  those  who  are 
so  unfortunate  as  to  be  under  the  necessity  of  wearing 
substitutes  for  lost  natural  dentures. 

"The  trouble  is  not  with  the  manufacturers;  they 
supply  the  demand.  The  fact  is,  the  requirements  of 
the  law  of  correspondence  have  not  been  sufficiently 
studied  by  the  profession.     The  first  study  of  the  den- 


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54 


DENTAL    PROSTHESIS   AND    METALLURGY. 


tist  who  aspires  to  the  dignity  of  artist,  when  propos- 
ing to  restore  a  lost  tooth,  should  be  how  to  restore  the 
natural  appearance  of  his  patient,  and  this  can  only  be 
effected  through  an  appreciation  and  observance  of  the 
temperamental  characteristics  and  the  law  of  correspond- 
ence or  harmony.  Age  and  sex  may  somewhat  modify 
the  requirements  in  a  given  case,  but  the  basal  fact  on 
which  he  should  proceed  is  temperament.  A  failure  to 
recognize  its  demands  will  result  in  failure, — from  an 
esthetic  standpoint.  A  knowledge  of  the  distinguish- 
ing characteristics  of  the  various  temperaments  and  the 
style  of  teeth  which  conform  to  nature's  type  in  the 
physical  organization  marks  the  difference  between  the 
dental  mechanic  and  the  dental  artist." 

From  the  foregoing  remarks  we  gather  the  following 
points  for  special  notice  : — 

In  Selecting  the  Teeth. — First,  their  shape  and 
character,  whether  the  sides  of  the  teeth  are  parallel  or 
divergent ;  whether  their  face  is  flat  or  curved  ;  whether 
they  are  thin  and  translucent,  or  thick,  opaque,  and 
massive. 

Second,  their  size ;  that  is,  their  width  and  length  and 
the  relative  width  and  length  of  the  anterior  teeth. 
Fig.  15  illustrates  typical  gum-sections  for  the  four 
basal  temperaments. 

Third,  their  shade.  Where  all  the  teeth  are  not  lost, 
and  the  remaining  teeth  are  in  good  condition,  an 
effort  should  be  made  to  match  the  natural  teeth  as 
accurately  as  possible.  Where  only  one  or  two  teeth 
are  missing  it  is  better  to  select  several  and  match  them 


SELECTION    AND    ARRANGEMENT   OF    TEETH. 


55 


in    the   mouth,  as  we  often  find   that    two   teeth  may 
closely   resemble    each   other,  yet  when   tried    in   the 


Fig.  15. 


Bilious. 


Nervous. 


mouth  it  is  seen  at  once  that,  though  little  different  in 
color  or  tone,  one  is  far  better  than  the  other.     Where 


56 


DENTAL   PROSTHESIS   AND    METALLURGY. 


full  sets  are  required,  the  age  and  temperament  of  the 
patient  should  be  the  principal  guide. 


Sanguineous. 


Lymphatic. 


Fourth,  the  position  of  the  pins.     Pins  are  arranged 
transversely  and  perpendicularly,  and  are  known  as  cross 


SELECTION    AND    ARRANGEMENT    OF    TEETH.  57 

and  straight  pins,  respectively.  In  metal  work,  that 
is,  for  metal  plates  or  crown-  and  bridge-work,  straight- 
pin  teeth  should  be  used  wherever  possible  and  the 
cross-pins  avoided,  for  the  following  reasons:  (i)  The 
position  of  the  pins  weakens  the  body  of  the  tooth.  (2) 
Their  position  makes  the  strain  upon  the  tooth  greater, 
as  it  gives  increased  leverage  between  the  pins  and  the 
cutting  edge.  (3)  There  is  less  liability  of  cracking 
the  teeth  in  soldering,  as  so  much  metal  is  not  brought 
at  one  point. 

In  Arranging  the  Teeth. — First  in  importance 
is  the  center  or  median  line,  which  is  regulated  by  the 
line  upon  the  wax  bite.  The  median  line  should  not 
be  indicated  at  one  point  alone,  say  at  the  cutting 
edges,  and  the  teeth  slanting  to  the  right  or  left,  as  is 
frequently  seen,  but  it  should  exactly  divide  the  space 
between  the  central  incisors  for  their  entire  length. 

Second,  the  slant  of  the  teeth.  The  teeth,  especially 
those  in  the  anterior  part  of  the  mouth,  beginning  with 
the  central  incisors,  should  lean  slightly  toward  the 
median  line.  The  slant  should  usually  be  the  greatest 
in  the  central  and  lateral  incisors,  and  by  slight  varia- 
tions the  teeth  may  be  given  a  more  natural  appearance. 
Much  judgment  and  artistic  taste  may  be  displayed  in 
forming  the  slight  irregularities.  Care  should  always 
be  taken  not  to  overdo  it,  so  as  to  give  the  mouth  a 
crowded  and  confused  appearance. 

Third,  the  relative  length.  The  relative  length 
should  be  shown  by  the  articulating  wax  models.  This 
wax,  however,  should  be  removed  and  laid  to  one  side, 
5 


58 


DENTAL    PROSTHESIS   AND    METALLURGY. 


where  it  can  be  kept  in  sight  as  a  guide,  and  then  after 
comparing  the  teeth  with  the  wax,  as  to  length,  etc., 
they  should  be  adjusted  by  the  eye.  The  wax  bite  in 
this  way  is  preserved  for  future  use  if  necessary.  It  is 
always  better  to  retain  this,  as  well  as  the  antagonizing 
casts  in  single  or  partial  cases,  until  the  plate  has  been 
satisfactorily  inserted. 

Fig.  16. 


Fourth,  the  re-posing  of  the  features.  The  wax  models 
should  act  as  a  guide  in  this  as  in  regulating  the  length 
of  the  teeth.  If  they  were  carefully  and  accurately 
formed  when  taking  the  bite,  they  would  faithfully  ex- 
press the  needs  of  the  case  in  restoring  the  features. 
And  with  an  observing  and  critical  eye  the  operator 
should  not  only  be  able  to  give  the  teeth  their  proper 
length  and  fulness,  but  by  building  up  and  carving  the 


SELECTION    AND    ARRANGEMENT    OF    TEETH.  59 

wax  about  them,  be  able  to  at  least  fairly  reproduce  the 
lost  portions  of  the  facial  contour.  In  doing  this  the 
expressional  value  of  the  cuspid  teeth  should  always  be 
kept  in  mind. 

There  are  so  many  points  of  expressional  value  in 
the  arrangement  of  the  teeth,  that  it  is  always  better  to 
try  them  in  the  mouth  before  they  are  fully  arranged, 
and  note  any  changes  that  may  be  necessary  to  make 
them  harmonize  with  the  general  features  of  the  patient. 

Fifth,  the  articulation.  The  most  important  point  to 
bear  in  mind  in  articulating  the  teeth  is  the  normal 
articulation  of  the  natural  teeth.  The  student  should 
study  the  wonderful  mechanical  adaptability  of  these 
organs  whenever  the  opportunity  is  afforded.  Fig.  16 
is  a  typical  illustration.  Observe  that  all  the  teeth  ex- 
cept the  inferior  central  incisors  and  the  superior  third 
molars  have  two  antagonists  in  articulation. 

In  arranging  the  teeth  upon  the  wax  plates,  some 
prefer  to  adjust  the  inferior  incisors  first,  while  others 
claim  that  the  superior  central  incisors  should  first  be 
set  in  position.  The  latter  is  doubtless  the  best  prac- 
tice, though  it  is  a  point  of  small  consequence  if  the 
proper  result  is  obtained.  In  arranging  the  posterior 
teeth  it  is  important  that  the  inner  cusps  should  occlude 
as  perfectly  as  those  of  the  outer  or  buccal  surface. 
The  greater  pressure  should  usually  be  brought  upon 
the  bicuspids  and  the  first  molars ;  and  this  bite  should 
be  perfect,  that  is,  these  teeth  should  touch  evenly  and 
at  the  same  time  upon  both  sides  of  the  mouth.  Such 
an  articulation   may  be  more   thoroughly  secured  by 


60  DENTAL    PROSTHESIS   AND    METALLURGY. 

removing  the  sharp  points  from  the  cusps  of  the  teeth. 
This  will  also  largely  overcome  the  "  clattering "  so 
often  noticed  in  artificial  teeth. 

Faulty  Articulation. — When,  in  a  finished  den- 
ture, the  articulation  is  found  to  be  slightly  faulty,  the 
false  touching  points  can  readily  be  recognized  and  re- 
moved with  the  corundum  wheel.  When,  however, 
the  articulation  is  found  to  be  so  far  out  of  the  way  as 
not  to  permit  of  satisfactory  correction,  the  entire  den- 
ture should  be  reconstructed.  This  occasionally  occurs 
to  the  inexperienced,  and  should  prove  to  them  a 
wholesome  lesson.  It  is  always  better,  as  has  been 
previously  suggested,  to  try  the  teeth  in  the  mouth 
while  they  are  yet  on  the  wax  plate,  when  any  imper- 
fection can  be  easily  remedied. 

Shaping  the  Cutting  Edges. — In  articulating  the 
teeth,  particularly  those  in  the  anterior  part  of  the 
mouth,  it  is  frequently  advisable  to  so  cut  and  shape 
the  edges  that  they  could  hardly  be  recognized  as  the 
same  teeth. 

Take,  for  instance,  a  person  of  the  sanguine  tempera- 
ment. Nature  gives  such  an  individual  teeth  that  are 
well  proportioned,  abounding  in  curves  arranged  in  a 
full,  round  arch,  with  an  articulation  that  is  moder- 
ately firm  and  corresponding  generally  to  the  contour 
of  the  face.  The  natural  occlusion  being  nearly  on 
end,  the  front  teeth  would  be  found  much  worn  away 
by  the  time  the  patient  would  be  apt  to  need  artificial 
substitutes. 

Imitating  this  worn  or  abraded  condition  gives  the 


SELECTION    AND    ARRANGEMENT    OF    TEETH. 


61 


artist  further  opportunity  to  display  his  skill.  After 
selecting  teeth  that  meet  the  requirements  as  nearly  as 
possible  in  size  and  color,  it  is  possible  to  so  change 
them  by  judicious  grinding  as  to  give  a  more  harmoni- 
ous expression  to  the  mouth.  This  may  be  accomplished 
with  either  plain  or  gum  teeth,  but  more  thoroughly 
where  plain  teeth  are  admissible,  that  is,  where  the  lip 

Fig.  17. 


is  long  enough  to  conceal  the  rubber  above  them.  Or, 
a  very  natural  appearance  may  be  given  by  securing  the 
teeth  at  the  depots  before  they  are  baked,  and  carve 
and  stain  them  according  to  the  requirements  of  the 
case  in  hand. 

Many  other  points  in  enhancing  the  appearance  of 
artificial  teeth  will  suggest  themselves  from  time  to 
time  to  the  thoughtful  student.  The  accompanying 
illustrations,  Figs.  17  to  21,  inclusive,  are  given  as 
typical  studies. 


62  DENTAL    PROSTHESIS    AND    METALLURGY. 

Fig.  18. 


Fjg.  19. 


Fig.  20. 


SELECTION   AND    ARRANGEMENT    OF    TEETH.  63 

Jointing  Gum  or  Block  Teeth. — By  the  judicious 
grinding  of  the  joints  in  gum  teeth,  whether  single  or 
arranged  in  sectional  blocks,  the  proper  shape  and  con- 
tour may  be  given  to  the  denture.  But  these  teeth  are 
not  susceptible  to  as  natural  and  artistic  arrangement  as 
the  plain  teeth.     The  latter,  however,  can  only  be  em- 


FlG.    21. 


PW*ffl|| 


ployed  where  the  teeth  are  to  rest  directly  upon  the 
natural  gums  as  shown  in  Fig.  21,  or  where  the  lips  are 
of  sufficient  length  to  entirely  conceal  the  gums. 

When  gum  teeth  are  used  every  care  should  be  taken 
to  so  grind  the  joints  that  their  surfaces  will  come  in 
perfect  contact,  and  not,  as  is  so  commonly  practiced, 
make  V-shaped  spaces.     As  each  block  is  thus  ground, 


64  DENTAL   PROSTHESIS   AND    METALLURGY. 

it  should  be  secured  to  the  trial  plate,  and  so  on  until 
all  the  teeth  are  in  position.  The  wax  plate  should  then 
be  neatly  shaped  to  resemble  the  finished  plate,  when  it 
is  ready  to  be  tried  in  the  mouth.  Then  after  making 
alterations,  if  necessary,  the  plate  should  be  replaced 
upon  the  cast  and  secured  by  passing  a  hot  spatula 
around  its  edge,  which  will  prevent  the  plaster  in  flask- 
ing  from  running  between  the  plate  and  the  cast. 

The  practice  of  packing  ill-fitted  joints  in  order  to 
make  them  impervious  to  the  rubber  and  to  hide  poor 
workmanship,  is  a  very  poor  expedient,  as  in  a  short 
time  these  materials  will  yield  to  the  action  of  the  fluids 
of  the  mouth,  when  the  joints  will  be  receptacles  for  the 
secretions,  and  soft  particles  of  food.  There  is  nothing 
that  will  so  surely  and  effectively  exclude  the  rubber  as 
accwate  jointing  and  careful  packing. 


FLASHING,    VULCANIZING,    AND    FIN- 
ISHING THE  RUBBER  BASE. 

Before  entering  upon  a  study  of  the  manipulation  of 
rubber  as  a  dental  base,  we  will  consider  the  com- 
position of  the  different  rubbers  used  for  this  purpose. 
The  bases  of  these  compounds  is  caoutchouc,  commonly 
called  India  rubber  or  gum  elastic* 

*  Caoutchouc  is  a  milky,  concrete  juice,  obtained  principally 
from  the  Siphonia  elastica,  or  Siphonia  Cahuchu,  a  South  American 
tree.  It  is  obtained  by  tapping  the  tree,  and  is  of  a  yellowish-white 
color,  but  gradually  grows  darker  upon  exposure.     It  takes  its  com- 


FLASKING,  VULCANIZING,  AND    FINISHING.  65 

After  the  crude  substance  has  been  passed  through  a 
triturating  machine  it  is  thoroughly  washed  and  dried 
to  remove  any  foreign  substances,  it  is  then  melted  and 
sulphur  and  the  coloring  matter  added.  It  is  due  to 
the  presence  of  the  sulphur  that  the  rubber  hardens 
when  brought  in  contact  with  heat  (vulcanization). 
The  more  sulphur  added,  the  harder  the  product. 
Manufacturers  as  a  rule  do  not  make  their  formulae 
known,  but  the  following,  selected  from  those  of  the 
late  Prof.  Wildman,  are  thoroughly  reliable  : — 

RUBBER  COMPOUNDS. 
Red.  Black. 

Caoutchouc,     ....  48  parts.       Caoutchouc,      ....  48  parts. 

Sulphur, 24     "  Sulphur, 24     " 

Vermilion, 36     "  Ivory  Black,    ....  24     " 

P'NK.  White  (Grayish). 

Caoutchouc,     .    .    .    .48  parts. 

o  1  1  ,,  Caoutchouc,     ....  48  parts. 

Sulphur, 24     " 

White  Oxid  of  Zinc,    .  30     "  Sulphur, 24 

,7       .,.  .       ..  White  Oxid  of  Zinc,    .  96     " 

Vermilion, 10     "  '       y 

Flasking. — After  removing  the  cast  and  denture 
from  the  articulator,  they  should  be  placed  for  a  few 
minutes  in  cold  water,  so  that  the  plaster  will  become 
saturated,  and  thus  prevent  its  absorption  of  the  water 

mon  name,  rubber,  from  the  fact  that  it  was  used  many  years  simply 
as  an  eraser  of  lead  pencil  marks.  It  is  insoluble  in  water  or  alco- 
hol, and  is  remarkable  for  its  elasticity.  Caoutchouc  melts  at  2480 
F.,  and  remains  in  an  unchangeable  fluid  state  up  to  5000  F. 


66 


DENTAL    PROSTHESIS    AND    METALLURGY. 


from  the  newly  mixed  plaster  in  flasking,  which  would 
in  a  measure  prevent  the  proper  adjustment  of  the  cast. 
When  the  plaster  has  been  thoroughly  mixed  (to  a 
creamy  consistency)  fill  the  lower  part  of  the  flask 
about  half  full  and  introduce  the  model,  slightly  in- 
clined at  first,  then  press  it  down  to  a  horizontal  posi- 
tion, well  imbedded  in  the  plaster.     By  this  means  the 


Fig.  22. 


air  is  excluded,  which  would  not  be  the  case  if  it  were 
forced  down  horizontally  at  once. 

The  height  of  the  plaster  about  the  denture 
determines  the  division  between  the  two  sections  of  the 
flask.  This  is  regulated  by  the  character  of  the  teeth 
invested.  If  they  are  teeth  (either  gum  or  plain)  that 
rest  upon  or  are  embedded  in  the  base  plate,  the  case 
should  be  invested  to  just  above  the  margin  of  the  wax 
(see  Fig.  22).      In  this  way  the  teeth  and  nearly  all  of 


FLASKING,  VULCANIZING,  AND    FINISHING. 


67 


the  wax  rim  will  be  embedded  in  the  upper  portion  of 
the  flask. 

When  the  necks  of  the  teeth  are  to  rest  upon  the 
natural  gum,  as  shown  in  Fig.  21,  the  investing  plaster 
should  extend  to  the  cutting  edges  of  these  teeth  so  as 
to  retain  them  in  the  lower  section  of  the  flask.  This 
is  illustrated  in  Fig.  23. 

Fig.  23. 


While  the  plaster  is  setting,  trim  the  surface  up  to  the 
shape  or  slant  desired,  avoiding  undercuts,  leaving  it  as 
smooth  as  possible.  After  it  is  thoroughly  set,  var- 
nish this  surface  with  shellac,  and  when  dry  give  it 
a  thin  coat  of  oil  or  the  soap  solution.  Care  should 
be  taken  not  to  allow  the  varnish  or  oil  to  come  in  con- 
tact with  the  teeth. 


68  DENTAL   PROSTHESIS   AND    METALLURGY. 

The  ring  or  upper  section  of  the  flask  should  now  be 
placed  on  the  lower  portion  which  contains  the  teeth. 
A  perfect  joint  should  be  secured  between  these  two  sec- 
tions, the  plaster  should  be  mixed  as  before,  and  poured 
into  this  ring  while  in  position,  jolting  the  flask  at  the 
same  time  to  induce  the  plaster  to  run  around  the  teeth 
perfectly  and  to  force  the  air  out..  After  the  flask  is  well 
filled,  the  top  piece  should  be  placed  in  position  and 
forced  home,  which  will  drive  out  any  surplus  plaster ; 
this  pressure  should  be  continued  until  the  plaster  has 
thoroughly  set. 

Fig.  24. 


Where  deep  undercuts  are  present,  one  of  two 

processes  may  be  adopted.  They  are  well  described  in 
the  late  Dr.  Alonzo  Beale's  article  in  the  "American 
System  of  Dentistry,"  where  he  says  :  "  First,  the  plas- 
ter in  the  lower  section  may  be  made  to  cover  the  wax 
rim  within  half  a  line  of  the  porcelain  gums.  This  will 
protect  the  cast,  so  that  it  will  not  be  fractured  when 
parting  the  flask  or  when  packing  the  rubber.  This 
method  is  represented  in  Fig.  24.  Or,  the  base  of  the 
cast  may  be  so  trimmed  that  the  undercut  will  approach 


FLASKING,  VULCANIZING,  AND    FINISHING. 


69 


as  nearly  as  possible  the  perpendicular,  as  seen  in 
Fig.  25.  When  the  latter  plan  is  adopted  the  flask, 
before  opening,  should  be  moderately  heated  in  water 
to  about  a  temperature  of  1200  F.  Allow  it  to  remain 
in  the  water  for  a  few  minutes,  so  that  the  heat  may 
penetrate  to  and  soften  the  wax.  Then  remove  the 
flask  and  separate  the  two  sections  carefully.  If  these 
directions   are   followed,   the  wax  will   generally   part 

Fig.  25. 


readily  from  the  teeth  and  plaster.  If  any  adheres  to 
the  pins,  it  should  be  carefully  washed  out  with  boiling 
water." 

The  necessity  for  removing  every  particle  of  wax  is 
due  to  the  fact  that  its  presence  destroys  the  integrity 
of  the  rubber  and  interferes  with  its  vulcanization.  It 
is  better,  therefore,  in  all  cases,  to  direct  upon  the  cast 
a  stream  of  boiling  water,  with  the  flask  placed  at  such 
an  angle  that  any  particles  of  wax  will  be  readily  car- 
ried off. 

Outlet  Grooves  or  Gates. — The  next  step  is  to 


7° 


DENTAL    PROSTHESIS    AND    METALLURGY. 


make  grooves  or 


gates  "  which  will  act  as  receptacles 
for  the  excess  of  rubber.  This  is  done  by  cutting  a 
groove  around  the  cast,  part  way  between  it  and  the 
margi  i  of  the  flask,  as  shown  in  Fig.  26.     The  groove 


Fig.  26. 


should  be  beveled  from  its  bottom  toward  the  casts  to 
within  about  one-sixteenth  of  an  inch  of  the  border. 
The  top  of  this  septum  is  then  slightly  scraped.  This 
must  be  carefully  done,  as  it  is  desirable  to  simply  trim 
off  the  sharp  edges  and  a  thin  and  uniform  layer  of  the 


FLASK1NG,  VULCANIZING,  AND    FINISHING.  7 1 

plaster  from  its  entire  surface.  This  will  more  readily 
allow  the  passage  of  the  surplus  rubber  into  the  annular 
groove.  This  method  was  first  suggested  by  Dr.  W. 
Storer  How,  in  The  Dental  Cosmos. 

The  old  method,  and  that  practiced  to-day  by  many, 
is  to  cut  radiating  grooves  about  one-fourth  of  an  inch 
apart,  leading  from  the  cast  to  the  larger  or  annular 
groove.  As  Dr.  How  says  of  this,  the  radial  gates 
really  defeat  the  true  objects  in  view  by  affording  too 
free  an  escape  of  the  softened  rubber,  thus  prevent- 
ing that  condensation  of  the  inclosed  material  which  is 
necessary  for  the  production  of  the  best  results. 

Before  packing  the  rubber  the  case  should  be  thor- 
oughly dried  and  the  cast  coated  with  something  to 
prevent  the  rubber  from  penetrating  the  pores  of  the 
plaster  and  adhering  to  its  surface,  thus  giving  a  smooth- 
ness to  the  palatine  surface  of  the  plate.  For  this  pur- 
pose tin-foil  or  liquid  silex  is  generally  used,  but  we  have 
found  excellent  results  can  be  secured  by  sprinkling 
lycopodium  or  soapstone  upon  the  surface  of  the  cast. 
This  should  then  be  thoroughly  brushed  off  with  a  jew- 
eler's brush  or  a  soft  brush  wheel,  leaving  the  surface 
of  the  model  with  a  high  polish. 

The  case  should  now  be  made  quite  warm,  by  placing 
it  in  an  oven  or  over  a  gentle  flame.  This  will  aid  very 
materially  in  packing  the  rubber,  as  it  will  more  readily 
adhere  to  a  warm  surface. 

Packing  Rubber. — Before  packing  it  is  important 
to  see  that  the  mold,  instruments  used,  and  the  rubber 
are  perfectly  clean.     Then  cut  the  rubber  into  narrow 


72  DENTAL   PROSTHESIS   AND    METALLURGY. 

strips  about  an  inch  in  length,  and  in  small  squares,  to 
pack  around  the  teeth,  also  one  or  two  larger  pieces  to 
cover  the  body  of  the  cast.  Place  these  pieces  upon  a 
metallic  plate  (tin  or  zinc)  over  a  pan  of  hot  water.  The 
small  pieces  of  rubber  should  now  be  carefully  worked 
beneath  and  between  the  platinum  pins,  with  small 
curved  and  straight  pointed  instruments.  Then  proceed 
to  fill  the  mold  by  adding  small  pieces,  one  at  a  time,  after 
each  successive  piece  has  been  thoroughly  impacted,  and 
finish  the  packing  process  by  adding  one  larger  piece, 
which  should  be  of  sufficient  size  to  cover  the  palate, 
with  a  smaller  piece  over  its  center.  This  will  make  the 
center  a  little  fuller  than  the  remainder  of  the  mold, 
so  that  when  the  sections  of  the  flask  are  brought  to- 
gether, the  rubber,  if  kept  sufficiently  hot,  will  be  forced 
gradually  to  the  margins  of  the  mold,  diminishing, 
thereby,  the  liability  of  moving  or  fracturing  the  gum- 
sections. 

After  packing  the  mold  the  upper  section  of  the  flask 
should  be  placed  in  position,  the  bolts  should  then  be 
slipped  into  place,  and  the  nuts  turned  down  just 
enough  to  hold  all  in  their  proper  position. 

The  flask  should  now  be  placed  in  boiling  water  for 
about  one  minute,  then  removed,  and  the  nuts  turned 
down  carefully  and  evenly  until  considerable  resistance 
is  offered,  when  it  should  be  replaced  in  the  boiling 
water  and  the  process  repeated  until  the  two  sections 
are  brought  securely  together.  The  bolts  should  not 
now  be  loosened  until  the  case  has  been  vulcanized  and 
become  cold. 


FLASKING,  VULCANIZING,  AND    FINISHING. 


73 


The  flask-press,  while  a  very  useful  instrument 
when  judiciously  employed,  should  not,  as  a  general 
thing,  be  used  by  students,  for  blocks  are  fractured, 
teeth  forced  out  of  position,  or  entire  cases  are  easily 
and  frequently  ruined  by  undue  force  being  exercised 
in  bringing  the  sections  together. 

If    the  foregoing  directions  have  been  closely  fol- 


Fig.  27. 


lowed,  a   cross-section    of  the    flask   would   have    the 
appearance  shown  in  Fig.  27. 

Vulcanizing. — That  the  student  may  understand  the 
chemistry  of  the  process  of  vulcanizing,  and  as  an  in- 
troductory to  the  more  general  considerations  of  the 
methods  and  appliances  employed  for  that  purpose, 
we  quote  as  follows,  from  a  lengthy  paper  by  F.  A. 
Boeck,  of  Berlin,  Germany,  which  was  translated  by 
6 


74  DENTAL   PROSTHESIS   AND    METALLURGY. 

Dr.  Louis  Ottofy :  "Chemistry  teaches  that  all  vege- 
table products,  such  as  wool,  starch,  the  leaves  and  sap 
of  plants,  consist  of  four  elements — oxygen,  nitrogen, 
hydrogen,  and  carbon.  In  no  plant,  or  the  product  of 
a  plant,  is  carbon  absent,  and  it  is  mostly  in  connection 
with  hydrogen  and  oxygen,  whereas  nitrogen  is  but 
seldom  present.  From  these  few  elements  nature  has- 
produced  all  that  earth  possesses  of  vegetable  growth, 
the  variety  and  difference  being  sometimes  only  the 
different  proportion  of  union  of  the  elements,  or  the 
addition  of  a  small  amount  of  acids,  bitter  substances, 
coloring  matters,  or  salts.  Rubber  consists  only  of  the 
above  elements,  namely,  CH ;  it  belongs,  therefore,  to 
the  class  known  as  the  hydrocarbons,  and  to  that  class 
of  these  in  which  C  predominates.  It  is  interesting  to 
notice  here  that  the  change  from  the  soft  to  the  hard,  as 
is  the  case  with  rubber,  is  the  property  of  all  vegetable 
products.  We  know  that  the  change  takes  place  by  the 
application  of  heat,  that  hydrogen  sulphid  (HS)  is 
formed,  and  that  the  process  takes  place  during  the 
exclusion  of  air.  This  process  is  chemically  the  same 
as  takes  place  in  the  dry  distillation  of  wood,  in  the 
changing  of  wood  into  coal,  and  of  resin  into  amber. 
If  wood  is  heated  in  the  open  air  it  burns ;  the  same  is 
the  case  with  rubber,  only  that  the  latter  burns  slower 
on  account  of  its  larger  percentage  of  C.  If  wood  is, 
however,  heated  in  the  absence  of  air,  as  is  the  case  in 
making  illuminating  gas,  quite  peculiar  substances  are 
eliminated  from  the  wood,  the  illuminating  gas,  which 
escapes,  and  three  substances :    a  watery  pyroligneous 


FLASKING,  VULCANIZING,  AND    FINISHING.  75 

acid  (wood  vinegar),  a  thick,  viscid  liquid  (wood  tar), 
and  a  solid  mass  (charcoal). 

"  The  wood  tar  is,  like  rubber,  of  a  resinous  nature ; 
it  consists  of  the  oil  of  wood  tar  and  a  liquid  substance, 
burnt  resin.  Both  become  hard  on  cooling;  the  former 
is  the  well-known  paraffin,  the  latter  the  equally  well- 
known  pitch. 

"The  rubber  undergoes  similar  changes.  If  it  is 
heated  while  excluded  from  air,  as  is  the  case  in  vulcan- 
izing, there  escapes  (as  in  the  case  of  wood,  illuminat- 
ing gas),  the  hydrogen  sulphid,  and  there  remains. a 
plastic,  which  hardens  on  cooling,  as  in  the  case  of 
pitch  or  paraffin,  and  we  have  our  hard  rubber. 

"  If  we  think  over  this  subject,  it  becomes  clear  to  us 
why  sulphur  is  added  to  the  rubber.  By  dry  distillation 
one  or  more  equivalents  of  hydrogen  separate  from  the 
mass  and  remain  gaseous,  or  unite  with  other  substances 
present  and  form  a  liquid,  thus  leaving  behind  a  hard 
substance,  which  consists  mainly  of  C.  It  is  well  known 
that  the  hardest  substance,  the  diamond,  is  pure  C.  The 
more  equivalents  of  H  that  remain,  the  softer  is  the 
substance,  as  in  the  following  scale :  coal,  resin,  pitch, 
axle  grease,  oil,  ethereal  oils,  gases.  The  same  is  the 
case  in  the  reversed  order.  If,  from  the  soft  rubber, 
hard  rubber  is  to  be  made,  it  is  necessary  to  remove  from 
it  one  or  more  equivalents  of  H.  This  is  the  case  in 
dry  distillation.  If  there  is  no  dry  distillation,  if  the 
rubber  was  heated  under  free  admission  of  air,  the  C 
would  immediately  unite  with  the  O  of  the  air,  forming 
carbonic  acid,  combustion  would  take  place,  even  though 


76  DENTAL   PROSTHESIS    AND    METALLURGY. 

it  would  be  slow  and  difficult.  This  cannot  take  place 
when  the  air  is  excluded;  the  carbon  remains  unchanged, 
whereas  the  H  finds  a  substance  with  which  it  is  more 
willing  to  unite  at  a  high  temperature.  This  substance 
is  the  S,  and  the  union  of  these  forms  HS,  which  is  well 
known  to  us  by  its  odor.  When  this  union  has  taken 
place  a  chemical  change  has  been  accomplished,  a  new 
substance  has  been  produced,  the  gas  escapes ;  the 
remainder,  the  product  of  the  distillation,  contains  less 
H  than  the  raw  rubber,  and  on  cooling,  like  pitch,  it 
becomes  a  harder  substance  by  its  containing  more  C 
than  before. 

"  My  hypothesis,  therefore,  leads  me  to  the  following 
conclusion  : — 

"  The  hardening,  or  so-called  vulcanizing,  of  rubber  is 
the  changing  of  caoutchouc  into  a  resin-resembling  sub- 
stance by  the  process  of  dry  distillation,  a?id,  namely,  by 
the  removal  of  one  equivalent  of  H.  The  addition  of  S 
serves  only  as  a  base,  which  is  indifferent  toward  C,  but 
unites  with  H  by  virtue  of  a  strong  chemical  affinity 
existing  between  H  and  S,  which  forms  a  new  com- 
pound, H  S,  which  escapes  as  a  gas." 

Appliances  Used. — The  apparatus  in  which  the 
rubber  (prepared  and  flasked  as  has  been  directed)  is 
hardened  by  the  action  of  heat  is  known  as  a  vulcanizer. 
It  consists  of  a  copper  boiler  with  a  screw  top,  having 
connected  with  it  a  steam  gauge  or  thermometer  for 
regulating  the  amount  of  steam  necessary  to  vulcanize 
the  rubber;  the  steam  gauge  is  no  doubt  the  safest  and 
most  reliable.     It  is  also  supplied  with  a  safety-valve  or 


FLASKING,  VULCANIZING,  AND    FINISHING. 


77 


blow-off,  to  allow  the  escape  of  steam  and  prevent  ex- 
plosion when,  from  negligence,  it  should  become  over- 
heated.    There  are  numerous  forms  of  vulcanizers  upon 


Fig.  28. 


the  market ;  one  of  the  best   of    these,  known  as  the 
Philadelphia  Vulcanizer,  is  shown  in  Fig.  28. 

This  vulcanizer  is  given,  ready  for  use,  in  Fig.  28. 
Its  simplicity  is  shown  in  Fig.  29,  a,  b  and  c.     a  rep- 


78 


DENTAL   PROSTHESIS   AND    METALLURGY. 


resents  the  copper  bowl ;  b,  the  ring  or  socket  with'an 
annular  rib  on  the  top,  which  supports  the  copper 
bowl,  while  c  shows  the  tripod  yoke  or  lid.     There  are 

Fig. 29. 


no  bolts,  nuts,  wrench,  nor  bed-plate  required,  making 
it  altogether  the  simplest  and  most  convenient  vul- 
canizer  extant. 

Methods  Employed.— After   the  flask   has  been 
carefully  packed  and  closed,  place  it  in  the  vulcanizer 


FLASK1NG,  VULCANIZING,  AND    FINISHING.  79 

with  water  enough  to  fill  the  boiler  about  one-third  full, 
not  more.  If  two  or  three  cases  are  to  be  vulcanized  at 
the  same  time,  the  same  amount  of  water  is  sufficient 
Place  the  top  of  the  vulcanizer  in  position  and  screw 
down.  Light  the  lamp  or  gas  and  regulate  it  so  as  to 
require  a  half  hour  to  raise  the  temperature  to  the 
vulcanizing  point,  32o°F.,  or  120  pounds  pressure  by 
steam  gauge.  This  is,  of  course,  for  ordinary  work ; 
where  for  any  reason  the  rubber  is  unusually  thick,  the 
time  should  be  extended  to  one  hour,  or  an  hour  and  a 
half,  or  more,  according  to  the  thickness  of  the  mass, 
as  the  heat  if  run  up  too  rapidly  will  cause  the  rubber  to 
become  spongy  or  porous. 

When  the  vulcanizing  point  is  reached  the  flame 
should  be  slightly  lowered,  so  that  the  temperature  will 
remain  uniform  throughout  the  operation.  The  time  re- 
quired to  effect  vulcanization  is  usually  one  hour  from 
the  time  the  heat  reaches  the  vulcanizing  point.  When 
this  time  has  expired,  cut  off  the  flame  and  allow  the 
vulcanizer  to  cool  to  at  least  200,  when,  if  necessary,  it 
can  be  hastened  by  placing  it  in  cold  water.  As  Dr. 
Howe  says,  in  his  paper  upon  the  subject,  certain  ad- 
vantages are  obtained  by  allowing  the  cooled  flask  after 
the  vulcanization  to  remain  unopened  over  night,  or  at 
least  for  several  hours.  A  molecular  accommodation 
of  an  annealing  character  thus  occurs,  with  a  conse- 
quent diminution  of  liability  to  warp  the  plate  or  break 
the  porcelain  sections.  The  long-continued  retention 
of  the  denture  on  the  model  within  the  flask  tends  also 
to  keep  the  plate  in  shape  until  its  form  becomes  per- 


So  DENTAL   PROSTHESIS    AND    METALLURGY. 

man  en  t ;  whereas  a  quickly  cooled  and  immediately 
finished  denture  may  surprise  the  dentist  by  unaccount- 
ably changing  shape,  or  by  showing  cracks  in  the  gum 
sections;  in  fact,  either  of  these  serious  defects  may 
result  after  the  denture  has  been  hastily  finished  and  the 
patient  dismissed  only  to  return  in  a  few  days  with 
dissatisfaction,  because  of  the  meantime  occurrence  of 
the  defects.     It  is  worth  while  to  take  time  to  save  time. 

The  Finishing  Process. — When  the  plate  is  re- 
moved from  the  flask,  all  adhering  plaster  should  be 
carefully  detached  with  a  pointed  knife,  after  which  it 
should  be  thoroughly  cleansed  by  the  use  of  a  stiff 
brush  and  water.  The  rubber  should  then  be  reduced 
to  the  desired  thickness  and  shape  by  the  use  of  scrapers, 
files,  lathe-burrs,  and  chisels.  Fig.  30  represents  some 
of  the  standard  forms  of  these  tools. 

After  this  is  obtained  and  the  surface  of  the  rubber 
is  rendered  somewhat  smooth  and  uniform,  fine  sand- 
paper should  be  used  to  remove  the  marks  and  scratches 
left  by  the  use  of  the  tools.  The  final  finish  is  then 
given  by  first  using  finely  pulverized  pumice-stone, 
on  felt  or  cork  wheels  or  cones,  driven  by  a  lathe  ; 
this  will  give  a  smooth  surface.  The  case  should  then 
be  thoroughly  washed,  when  the  polish  is  given  by  pre- 
pared chalk  or  whiting.  This  is  best  applied  upon  a 
cotton  or  soft  brush  wheel.  In  using  the  polishing 
materials  they  should  be  kept  freely  saturated  with  cold 
water  throughout  the  operation.  The  denture  should 
then  be  thoroughly  washed,  when  it  will  be  ready  for 
insertion  in  the  mouth. 


Fig.  30. 


8l 


82 


DENTAL   PROSTHESIS    AND    METALLURGY. 


Pink  Rubber  Gum. — In  the  construction  of  a 
denture,  where  "plain"  teeth  are  used  and  where  the 
artificial  gum  is  to  be  made  of  pink  rubber,  the  best 
practice  is  as  follows,  which  we  quote  from  the  late  Dr. 
Alonzo  Beal's  teaching: — 

After  vulcanization,  enough  of  the  rubber  surface 
representing  the  gum  should  be  removed  from  around 
and  between  the  porcelain  teeth  to  allow  space  for  a 
thin  layer  of  pink  rubber.  The  surface  thus  exposed 
should  be  roughened  and  trimmed  out  well  between  the 

Fig.  31. 


necks  of  the  teeth,  as  shown  in  Fig.  31,  and  then  coated 
with  a  solution  of  red  rubber  dissolved  in  chloroform. 
This  solution  should  be  about  the  consistency  of  thin 
cream.  A  strip  of  pink  rubber  large  enough  to  cover 
this  whole  surface  should  be  softened  over  boiling  water 
and  pressed  tightly  against  the  red  rubber  plate,  care 
being  taken  to  force  it  well  in  between  the  teeth,  using 
a  smooth,  clean  instrument  for  the  purpose.  To  vul- 
canize this  it  is  not  necessary  to  flask  the  denture  in 
the  usual  manner.  Wet  the  plate  and  place  plaster-of- 
Paris  in  the  palatal  surface ;  fill  the  flask  with  plaster 


FLASKING,  VULCANIZING,  AND    FINISHING.  83 

and  embed  the  denture  in  it,  and  place  the  lid  on. 
When  the  plaster  is  hard,  introduce  the  bolts,  and  vul- 
canize thirty-five  minutes  at  3200  F.  When  the 
vulcanizer  is  cold  remove  the  flask  and  carefully  sepa- 
rate the  plaster  from  the  denture.  The  plat  should 
be  trimmed  and  polished  in  the  usual  way.  When 
polished  and  thoroughly  cleaned  the  pink  rubber 
should  be  bleached,  and  thus  rendered  brighter,  by 
placing  the  denture  in  the  sun  in  a  covered  glass  vessel 
partially    filled    with    alcohol.     All    trimming    should 

Fig.  32 


be  completed  before  bleaching,  as  only  the  surface  of 
the  rubber  is  changed  in  color.  Fig.  32  shows  the 
finished  case. 

Gold  Backing  and  Tongue. — In  partial  cases 
where  the  bite  is  so  close  that  the  antagonizing  teeth 
come  so  near  the  gum  that  the  thin  neck  of  rubber  run- 
ning from  the  plate  to  the  tooth  or  teeth  would  be  too 
frail  to  support  them,  teeth  with  gold  backings  and 
tongues  should  be  used.  In  preparing  such  a  tooth, 
select  a  suitable  plate  tooth  and  grind  it  to  fit  the  plaster 
model ;   then  fit  the  backing  and  tongue  to  the  tooth, 


84  DENTAL    PROSTHESIS   AND    METALLURGY. 

arrange  them  upon  the  cast  to  secure  the  proper  bend 
and  angle  for  the  tongue  (See  Fig.  33),  cement  them 
together,  invest,  and  solder. 

That  portion  of  the  gold  plate  to  be  embedded  in  the 
rubber  should  have  small  gold  or  platinum  pin-heads 
soldered  to  it,  or  it  should  be  perforated  in  several 
places  as  illustrated, — the  latter  is  probably  the  best 
practice, — to  secure  a  better  union  between  the  gold 
and  the  rubber. 

Gold   Clasps. — In  attaching  gold  clasps  to  rubber 

Fig.  33.  Fig.  34. 


plates  the  same  method  can  be  employed,  that  is,  by 
either  attaching  small  pin-heads  or  perforating  the  gold 
tongue  which  is  to  extend  into  the  rubber.  (See  Fig. 
34.)  In  making  these  attachments  they  should  be  so 
arranged  that  they  will  be  well  embedded  in  the  rubber 
when  the  plate  is  finished.  In  such  cases  care  must  be 
taken  in  packing  the  rubber  about  the  clasps.  The 
space  between  the  pins  or  tongue  and  the  cast  should  be 
packed  well  with  rubber,  so  that  when  the  flask  is  closed 
the  force  will  not  displace  the  tooth  or  clasp. 


CELLULOID    AS    A    DENTAL   BASE.  85 

CELLULOID  AS   A  DENTAL  BASE. 

In  taking  up  the  study  of  celluloid,  Dr.  Richardson 
in  his  treatise  upon  "Mechanical  Dentistry  "  says  : 
The  employment  of  celluloid  in  prosthetic  dentistry, 
though  of  somewhat  recent  date,  and  notwithstanding 
the  very  general  failure  which  attended  its  first  intro- 
duction into  practice,  came  rapidly  into  very  general 
professional  favor  as  a  cheap,  convenient,  and  serviceable 
base  for  artificial  dentures.  With  the  more  recent  im- 
provements in  the  manufacture  and  seasoning  of  blanks, 
more  perfectly  adapted  appliances  for  molding,  and  a 
more  extensive  acquaintance  with  the  peculiar  and  dis- 
tinctive characteristics  of  this  material,  it  has  super- 
seded, in  a  great  measure,  all  other  known  plastic 
vegetable  substances  for  the  purpose  indicated. 

That  celluloid  possesses  many  important  qualities 
which  commend  its  employment  as  a  base  in  preference 
to  rubber  can  hardly  be  questioned.  It  is  more  in  har- 
mony with  the  soft  tissues  of  the  mouth,  more  cohesive 
in  texture,  approximates  more  nearly  the  natural  gum 
color,  contains  far  less  vermilion  pigment  in  its  com- 
position, and  is  less  objectionable  by  reason  of  the  com- 
parative cleanliness  accompanying  its  manipulation. 

The  chief  objection  urged  against  celluloid  as  a  base 
is  its  low  power  of  transmitting  caloric,  but  it  is  believed 
to  be  less  objectionable  in  this  respect  than  rubber. 
Both  are  poor  conductors,  and  the  soft  tissues  of  the 
mouth  in  contact  with  either  suffer,  in  some  degree,  as  a 
consequence  of  this  property. 


86  DENTAL   PROSTHESIS   AND    METALLURGY. 

Celluloid,  as  at  present  produced  and  when  properly 
manipulated,  does  not,  in  any  appreciable  degree, 
undergo  change  of  form  after  molding  by  warping  either 
in  or  out  of  the  mouth,  as  was  formerly  the  case,  nor, 
it  is  believed,  does  it  absorb  the  oral  secretions.  It 
loses  somewhat  the  freshness  and  clearness  of  its  original 
pink  color  after  having  been  in  use  for  some  time,  in 
many  cases  in  a  very  marked  degree. 

Though  not  bearing  so  perfect  a  resemblance  to  the 
complexion  of  the  healthy  gum  tissue  as  the  porcelain 
imitations,  yet  the  near  approximations  of  celluloid  to 
the  desired  color  makes  the  use  of  single  plain  teeth  ad- 
missible for  permanent  dentures,  and  this  is  unquestion- 
ably its  crowning  merit,  and  makes  it  the  most  desira- 
ble of  all  the  so-called  cheap  bases.  The  indiscriminate 
and  almost  universal  employment  of  block  or  sectional 
gum  teeth  in  connection  with  rubber  has,  it  may  be 
safely  affirmed,  done  more  to  degrade  the  prosthetic 
department  of  dental  practice  than  all  other  causes 
combined.  The  optional  arrangement  of  each  tooth  to 
meet  the  requirements  of  special  cases  in  respect  to  ex- 
pression, articulation,  and  antagonism  is  one  of  the  ab- 
solute and  indispensable  requirements  of  a  perfect  arti- 
ficial denture.  A  more  general  recognition  of  this  im- 
portant fact  must,  sooner  or  later,  lead  to  the  entire 
abandonment  of  rubber  in  connection  with  ready-made 
sectional  gum  teeth.  "Taking  into  view  all  its  quali- 
ties," says  a  well-known  writer,  "and  leaving  out  the 
question  of  freedom  from  monopolies,  the  conclusion  is 
that  celluloid  has  the  potentialities  which  should  de- 


CELLULOID    AS    A    DENTAL   BASE.  87 

throne  rubber,  and  establish  itself  as  the  best  of  the 
cheap  bases." 

Composition. — Celluloid  is  composed  of  pyroxy- 
lin,* camphor,  oxid  of  zinc,  and  vermilion  in  pro- 
portions of  about  100  parts  of  pyroxylin,  40  of  camphor, 
2  of  oxid  of  zinc,  and  .06  of  vermilion. 

Manner  of  Preparing  Cast. — It  is  necessary  to 
have  a  harder  and  stronger  cast  than  for  rubber  work. 
This  is  due  to  the  inferior  plasticity  of  celluloid  when 
exposed  to  the  heat,  and  the  consequent  greater  amount 
of  pressure  required  to  mold  it.  To  secure  these  impor- 
tant qualities,  the  very  best  hard-setting  plaster  should 
be  used,  or  a  small  quantity  of  marble-dust  may  be 
mixed  with  the  plaster.  A  metal  cast,  however,  will 
give  better  results,  especially  in  case  of  deep  undercuts. 
In  this  case  block-tin  or  Babbitt  metal  may  be  used, 
and  can  be  poured  directly  into  the  plaster  impression. 
The  cavity  for  the  vacuum  chamber  should,  of  course, 
be  cut  in  the  impression  before  the  metal  is  poured. 

When  metal  is  employed,  a  shell  is  more  advantageous 
than  a  solid  cast ;  and  a  plate,  where  there  are  any  con- 
siderable undercuts,  can  be  more  readily  detached  from 
the  former.  But  before  the  cast  is  run,  whether  it  be 
from  metal  or  plaster,  the  vacuum  chamber,  if  used, 
should  be  carved  in  the  impression. 

*  Pyroxylin,  commonly  known  as  gun-cotton,  is  made  by  macerat- 
ing cotton  wool — though  linen,  hemp,  etc.,  are  sometimes  employed 
— in  a  strong  mixture  of  nitric  and  sulphuric  acids  for  15  hours, 
when  it  should  be  washed  thoroughly  and  dried.  The  proportions 
are:  cotton-wool,  x/2  oz. ;  nitric  acid,  3^  ozs. ;  sulphuric  acid,  4  ozs. 


88 


DENTAL    PROSTHESIS    AND    METALLURGY. 


To  Make  a  Hollow  Metal  Cast. — Prepare  the 
impression  as  instructed  for  running  cast,  or  else  secure 
mold  in  sand  from  plaster  cast,  then  fuse  pure  block- 


Fig.  35. 


tin  and  pour  in  the  usual  manner.  The  metal  cools 
first  at  the  surface  ;  by  taking  advantage  of  this  fact  and, 
after  waiting  a  few  seconds,  inverting  the  mold  and 
quickly  pouring  out  the  central  fluid,  a  thin  metal  shell 


CELLULOID    AS    A    DENTAL   BASE.  89 

can  be  secured.  When  obtained  it  can  be  filled  with 
plaster,  which  will  form,  in  fact,  a  metal -faced  plaster 
cast.  When  the  case  is  finished  and  the  plaster  removed, 
the  edges  of  the  shell  may  be  drawn  in  with  a  pair  of 
pliers,  which  will  allow  it  to  be  readily  removed  from 
the  undercut  spaces. 

The  manner  of  taking  the  bite  and  articulating  the 
case,  as  well  as  the  arrangement  of  the  teeth,  is  pre- 
cisely the  same  as  has  been  directed  for  rubber  work ; 
more  pains  is  taken,  however,  in  carving  and  model- 
ing. 

Carving. — Dr.  W.  W.  Evans,  in  the  "American  Sys- 
tem of  Dentistry,"  writes  upon  the  subject  as  follows: 
"It  is  a  very  simple  performance  (carving)  if  we  only 
study  a  little  from  nature  —  take  a  few  impressions 
of  natural  gums  and  teeth  in  health  and  in  disease, 
regular  and  irregular,  with  spaces  from  lost  teeth  and  so 
on.  With  models  of  this  kind  before  us,  and  a  remem- 
brance of  the  face  of  which  we  intend  to  restore  the 
features,  the  case  is  not  a  difficult  one.  I  use  in  my  own 
carving  three  little  double-end  tools,  represented  in 
Fig.  35,  the  uses  of  each  of  the  points  of  which  I  will 
now  explain.  Fig.  36  presents  a  full  set  of  teeth  in  pro- 
cess of  carving,  the  lower  half,  shown  by  B,  having  on 
it  the  rough  wax,  as  dropped  there  carelessly  while 
grinding  and  adjusting  the  teeth,  the  upper  denture,  at 
C,  showing  where  the  wax  had  been  cut  away  from  the 
teeth  in  scallops  by  the  straight-bladed  knife  of  carver 
No.  2,  and  roughly  shaped  up  with  the  spoon  of  the 
7 


9° 


DENTAL    PROSTHESIS    AND    METALLURGY. 


same  instrument.  Next  is  used  the  smaller  spoon-end 
of  No.  i  to  form  the  fossae  or  depressions  lying  between 
the  roots,  and  the  curved  knife-blade  of  the  same  to  go 
around  the  teeth  on  the  palatal  surface. 

"  Having  carved  the  wax  in  this  way,  forming  festoons 
or  exposing  roots,  as  the  case  may  require,  take  a  spirit 
lamp  with  a  small  flame  and  an  air-bulb,  which  is  better 
than  a  blow-pipe,  and  by  gently  puffing  upon  the  wax 

Fig.  36. 


smooth  away  the  rough,  irregular  projections  while 
retaining  the  larger  undulations  of  the  form  desired. 
We  are  now  ready  for  the  tin-foil  and  stippling.  Take 
a  strip  of  No.  60  tin-foil,  a  little  wider  than  the  outside 
surface  of  the  gum,  and  by  commencing  at  one  side 
with  the  broad  end  of  the  ivory-pointed  carver,  No.  3, 
burnish  the  tin  down  smoothly  and  uniformly  over  the 
entire  surface,  occasionally   using  the  pointed  end  to 


CELLULOID    AS    A    DENTAL   BASE.  9 1 

work  between  the  teeth,  and  the  straight  blade  of 
carver  No.  i  to  cut  the  tin  from  around  the  teeth. 
The  inside  of  the  model  is  treated  in  the  same  way, 
except  that  a  narrow,  V-shaped  piece  is  cut  from  the 
tin  before  placing  it  on  the  palatal  surface,  to  avoid 
folding,  and  that  the  entire  outer  edge  of  the  plate  is 
trimmed  around.  The  stippling  is  done  with  an 
ordinary  blunt-pointed  excavator,  or  with  a  suitable 
engine  plugger  that  will  give  a  reacting  blow.  If  done 
delicately  and  closely,  the  effect  of  the  stippling  is  very 
pleasing." 

Manner  of  Flasking. — The  flasking  or  investing  of 
the  case  should  receive  quite  as  much  care  as  in  rubber 
work.  First  mount  the  model  high  in  the  shallow  half 
of  the  flask,  especially  designed  for  celluloid.  Now 
pour  in  thin  plaster  until  it  just  reaches  the  lower  edge 
of  the  plate.  When  the  plaster  is  set  sufficiently,  trim 
it  to  the  proper  shape  for  separating,  and  then  coat  it 
with  the  liquid  soap.  Place  the  deep  ring  of  the  flask 
in  position  and  very  carefully  fill  with  thin,  well-mixed 
plaster.  Place  on  the  top,  wash  the  outside  of  the  flask 
to  remove  all  the  surplus  plaster,  then  place  it  under 
gentle  pressure  for  half  an  hour,  or  until  the  plaster  has 
thoroughly  set. 

When  ready  to  separate,  place  the  flask  in  hot  water 
for  a  few  minutes,  when  the  sections  can  be  readily 
separated  ;  after  this  is  done  remove  with  a  suitable  in- 
strument all  the  wax  that  is  loose  and  easily  detached, 
then  pour  a  small  stream  of  boiling  water  upon  the  case 
until    every   particle    of    wax    is   washed    out.      Care 


92 


DENTAL    PROSTHESIS    AND    METALLURGY. 


should  be  taken  at  the  same  time  not  to  disturb  the  tin- 
foil. 

Outlet-grooves  or  Gates. — There  are  a  number 
of  methods  of  cutting  vents  or  gates  for  surplus  mate- 
rial, but  the   following,   which    is   about   as   practiced 

Fig.  37. 


by  Dr.  Evans,  is  probably  the  best.  The  upper  half 
of  the  flask  with  piece  invested  is  shown  in  Fig.  37. 
The  wax  has  been  washed  out,  exposing  to  view  the 
roots  of  the  teeth,  platinum  pins,  etc.,  as  ready  to 
receive  the  base  plate ;  the  stippled  tin-foil  is  clinging 
to  the  sides  of  the  plaster,  and  the  reverse  or  female 


CELLULOID    AS    A    DENTAL    BASE. 


93 


matrix,  a,  from  the  elevated  portion,  a,  on  the  male  half 
of  flask.  Fig.  38,  e,  indicates  a  portion  of  a  cut  away, 
illustrating  the  manner  of  forming  vents;  in  this  cut  it 
is  only  carried  half  around,  so  as  to  show  before  and 
after  preparing.  Commence  by  cutting  a  deep  groove 
all  around   the  piece  close   to  the  flask  and  gradually 

Fro.  -8. 


tapering  up  to  the  tin-foil  or  the  margin  of  the  plate, 
marked  c.  By  this  arrangement  the  material  has  free 
exit  all  around,  yet  may  not  come  out  too  rapidly. 
The  plaster  margins  are  not  likely  to  be  broken  away 
under  pressure,  as  the  vent  runs  out  almost  at  a  right 
angle,  thus  leaving  solid  walls.     Another  advantage  in 


94  DENTAL   PROSTHESIS   AND    METALLURGY. 

this  style  of  vent  is  that  after  the  two  halves  of  the  flask 
have  been  pressed  home  the  surplus  material  parts 
readily  from  the  piece,  leaving  very  little  to  dress 
up. 

Selecting  and  Preparing  the  Celluloid  Blank. 
— After  the  case  is  prepared  as  has  been  described,  a 
suitable  blank,  one  as  near  as  possible  the  size  and  form 
of  mold,  should  be  selected,  allowing  of  course  for  some 
little  surplus,  and  this  should  be  as  evenly  distributed  as 
possible. 

The  selected  blank  should  be  conformed  as  nearly  as 
possible  to  the  shape  of  mold  by  heating  it  in  boiling 
water  and  pressing  it  with  the  fingers  into  the  section 
containing  the  teeth  ;  after  which,  if  there  is  found  to  be 
more  surplus  than  is  necessary,  it  may  be  dressed  away, 
either  with  a  file,  knife,  or  small  saw,  first  softening  the 
blank  in  boiling  water  before  using  them. 

When  plaster  is  used  for  the  cast,  it  should  be  given 
a  thin  coat  of  oil,  liquid  soap,  or  liquid  silex,  or  its  sur- 
face should  be  rubbed  with  powdered  soapstone  or 
French  chalk,  to  prevent  the  adhesion  of  the  plaster  to 
the  plate.  More  perfect  results,  however,  can  be  ob- 
tained by  using  a  metal-faced  model. 

Molding. — Various  heaters  are  used  for  molding 
celluloid  into  dental  plates.  There  are  machines  de- 
signed to  use  glycerin  or  oil  and  others  for  steam  or 
dry  heat ;  and  while  with  careful  and  intelligent  man- 
ipulation satisfactory  results  may  be  obtained  with  all, 
some  of  them  may  possess  special  points  of  merit  which 
the  others  do  not.     The  limits  of  this  work,  however, 


CELLULOID    AS    A    DENTAL    BASE.  95 

will  only  permit  of  the  introduction  of  one  method,  the 
one  in  most  general  use. 

Hot  Moist  Air  Machines.* — Dr.  Richardson  says 
of  this  method  :  "In  the  use  of  these  heaters,  the  water 
with  which  the  plaster  is  impregnated  is  relied  upon  to 
produce  the  steam  necessary  to  carry  off  all  excess  of 
camphor  from  the  celluloid  in  the  process  of  molding. 
An  essential  point  by  this  method  is  to  have  the  plaster 
in  the  flask  thoroughly  wet,  and  this  may  be  better 
attained  by  setting  the  flask  in  a  vessel  of  water  before 
placing  it  in  the  heater.  To  provide  against  insufficiency 
of  moisture  in  the  plaster,  a  small  quantity  of  water 
may  be  introduced  into  the  tank  before  applying  heat. 

"  Fig.  39  represents  a  modeling  or  packing  machine 
of  the  class  here  spoken  of,  and  is  designated  as  the 
'  Best.'  The  inside  chamber  is  of  cast  iron,  surrounded 
by  a  sheet-iron  casing.  The  lid,  of  cast-iron,  forming 
a  part  of  the  clamp,  is  pierced  for  the  passage  of  three 
wrought-iron  screw-bolts — the  nuts  being  on  the  upper 
side  and  easy  of  access.  When  these  nuts  are  turned 
for  the  purpose  of  closing  the  clamp,  the  bottom  por- 
tion of  the  clamp  is  drawn  up  by  each  revolution  away 
from  the  flame,  thus  avoiding  the  danger  of  overheating 
the  plate,  and  securing  a  uniform  heat. 

"  The  bottom  of  the  cast-iron  chamber  and  the  lid  are 
pierced  with  holes  to  allow  a  circulation  through  the 
chamber,  for  the  purpose  of  carrying  off  the  camphor 
which  is  disengaged  in  the  process. 

*  So-called  "  Dry  Heat." 


96 


DENTAL    PROSTHESIS   AND    METALLURGY. 


"With  the  celluloid  blank  adjusted  to  its  proper 
position  in  the  flask,  the  latter  is  placed  in  the  clamp 
and  the  top  screwed  down  until  it  tightly  presses  the 
flask.  It  is  then  placed  in  the  oven  or  tank,  and  heat 
applied. 

Fig. 39. 


"  If  gas  is  used,  the  form  of  burner  shown  underneath 
the  heater  in  Fig.  39,  which  gives  a  pure  blue  flame 
without  smoke,  may  be  used.  If  gas  cannot  be  com- 
manded, however,  any  of  the  alcohol  or  kerosene  lamps 


CELLULOID    AS    A    DENTAL   BASE. 


97 


commonly  employed  in  vulcanizing  may  be  substituted  ; 
or  the  '  Hot  Blast  Oil  Stove,'  especially  adapted  to  the 
'  Best '  machine,  and  exhibited  in  connection  with  the 
latter  in  Fig.  40,  will  be  found  convenient  and  efficient. 


Fig.  40. 


"  Having  applied  the  heat,  it  is  of  the  first  import- 
ance that  unremitting  attention  should  be  given  to  the 
process  of  molding  until  it  is  completed.  If  pressure 
is  applied  before  the  celluloid  is  rendered  somewhat 
plastic,  or  too  great  force  is  exerted  during  the  earlier 


98  DENTAL   PROSTHESIS    AND    METALLURGY. 

stages  of  the  process,  and  without  sufficient  intervals  of 
rest,  there,  is  danger  of  crushing  or  fracturing  the 
model  and  of  impairing  the  articulation  by  displace- 
ment of  the  teeth.  On  the  other  hand,  the  nature  of 
the  celluloid  is  such  that  if  it  is  exposed  to  a  tempera- 
ture of  270,  without  being  under  pressure,  the  camphor 
evaporates,  and  the  material,  besides  being  rendered 
hard  and  intractable,  is  puffed  up,  exactly  as  a  loaf  of 
bread  is  raised  by  yeast,  and  filled  with  air  cells,  and 
thus  rendered  porous. 

"  Celluloid  begins  to  soften  at  about  225,  and 
will  then  yield  slightly  to  pressure,  but  this  should  be 
applied  very  gently  at  first,  with  no  more  force  than 
can  be  readily  exerted  with  the  thumb  and  finger.  As 
the  heat  increases,  and  the  celluloid  becomes  more  and 
more  plastic  and  yielding,  the  pressure  should  be  cor- 
respondingly increased,  but  always  interruptedly,  giving 
the  material  time,  between  each  turn  of  the  screw  or 
nuts,  to  escape  from  under  the  pressure.  No  consider- 
able amount  of  pressure  will  be  required  in  any  case 
until  near  the  close  of  the  operation,  when  the  mold  is 
completely  impacted,  and  the  excess  is  being  forced 
into  the  grooves  or  gateways  as  the  flask  comes  together. 

"  At  this  point  considerable  force  will  be  necessary  to 
close  the  flask  perfectly,  and  somewhat  longer  intervals 
of  time  should  occur  between  each  turn  of  the  screw  or 
nuts. 

"  During  the  progress  of  the  molding  the  flask 
should  be  withdrawn  occasionally  for  inspection.  If, 
in  the  case  of  central  pressure,  the  flask  is  found  to  be 


CELLULOID    AS.  A    DENTAL    BASE.  99 

closing  unevenly,  it  should  be  loosened  in  the  clamp 
and  readjusted  in  such  manner  as  to  correct  the  faulty 
approximation.  No  difficulty  will  be  experienced  in 
this  respect  in  the  use  of  clamps  provided  with  screw- 
bolts,  as  pressure  may  be  applied  at  any  point,  and  the 
flask  be  made  to  close  uniformly  without  the  necessity 
of  shifting  the  latter. 

"  The  moment  the  flask  is  completely  closed  the  heat 
should  be  turned  off  and  the  piece  allowed  to  cool 
gradually.  In  no  instance  should  the  flask  be  removed 
from  the  clamp  until  it  is  stone  cold.  In  cases  where 
the  material  is  of  extra  thickness,  or  where  the  shape  of 
the  blank  is  totally  altered,  longer  seasoning  is  advisa- 
ble, and  the  flask  should  be  placed  near  a  stove  or  over 
a  register  (keeping  it  closed  by  a  clamp)  for  half  a  day 
or  more,  at  a  temperature  of  not  over  1400.  If  these 
directions  are  observed,  no  trouble  from  warping  plates 
will  be  experienced." 

The  Finishing  Process. — After  the  flask  has  be- 
come perfectly  cold  the  sections  should  be  carefully 
separated  by  passing  a  knife-blade  between  them ;  a 
gentle  movement  will  cause  one  or  the  other  to  leave 
the  plaster,  when  the  remaining  one  is  easily  detached 
by  a  few  blows  from  the  hammer  on  its  edge.  Now 
trim  off  the  plaster  from  around  the  case,  wash  freely, 
cut  away  the  surplus,  and  remove  the  tin-foil.  The  case 
is  then  ready  for  finishing,  which  is  accomplished  with 
the  use  of  the  same  instruments  used  in  rubber  work. 

The  final  polish  is  given  first  with  felt  wheels  and 
pumice   stone,   and  afterward   with  brush-wheels     and 


IOO  DENTAL    PROSTHESIS   AND    METALLURGY. 

chalk,  taking  care  not  to  use  too  much  friction  lest  the 
plate  should  be  warped. 

Celluloid  Combined  With  Other  Bases.— The 
combination  of  celluloid  with  other  dental  bases,  such 
as  rubber,  gold,  and  aluminum,  is  deserving,  by  reason 
of  its  merits,  of  more  favorable  consideration  than  it  has 
heretofore  received.  In  commenting  on  this  method 
Prof.  Charles  J.  Essig  very  justly  remarks  "  That  we 
are  able  to  produce  an  artificial  denture  embracing  all 
that  is  good  in  metallic  and-vulcanite  work,  at  the  same 
time  avoiding  the  great  defects  of  each." 

The  manipulation  and  details  of  constructing  this 
class  of  dentures  is  thus  described  by  Dr.  Hunt,  of 
Indianapolis,  Ind.,  who  first  brought  it  to  the  notice 
of  the  profession  :  "  Take  the  impression,  make  metallic 
dies,  and  form  the  plate  as  for  work  in  the  ordinary 
way.  After  fitting  the  plate  in  the  mouth,  get  the 
articulation,  the  fulness  and  length  of  the  teeth,  remove 
the  wax  and  plate  from  the  mouth,  and  make  the  plaster 
articulation.  In  a  full  set,  after  separating  the  articula- 
tion, and  before  removing  the  wax  from  the  plate,  take 
a  small,  light  pair  of  dividers,  set  them  say  one  inch 
apart,  and  with  one  point  following  the  margin  of  the 
wax  representing  the  cutting  edge  of  the  teeth,  and 
the  other  point  marking  permanently  the  plaster,  you 
have  always  in  the  dividers  so  set,  a  gauge  for  the 
length  of  any  particular  tooth.  A  convenient  substi- 
tute for  the  dividers  may  be  formed  from  a  piece  of 
wire  of  convenient  length,  one-half  the  diameter  of  a 
common  excavator,  by  suitably  twisting  its  middle  for 


CELLULOID    AS    A    DENTAL    BASE.  IOI 

a  handle,  and  its  ends  being  sharpened,  and  pointing 
in  the  same  direction,  one  or  one  and  a  half  inches 
apart. 

"Thus  far  we  proceed  as  we  do  for  ordinary  gold 
work.  We  will  now  suppose  the  teeth  ground,  leaving 
as  much  space  between  the  teeth  and  plate  as  the 
plate  will  admit  of.  We  next  mark  with  a  sharp- 
pointed  instrument,  on  the  labial  surface  of  the  plate, 
each  point  where  it  is  necessary  to  place  a  loop  for 
purposes  hereinafter  described.  Then  apply  wax  to  ex- 
ternal or  labial  parts  of  the  teeth  and  plate,  in  any 
manner  sufficient  to  retain  the  teeth  in  position,  remove 
the  wax  from  the  lingual  parts  of  the  teeth  and  plate, 
and  mark  the  position  on  the  metal  and  solder  on  loops 
or  pins. 

"  Pickle,  dress,  and  polish  that  portion  of  the  plate  to 
be  exposed  to  view.  Bend  and  flatten  the  pins,  arrange 
the  teeth  according  to  the  articulation,  waxing  so  as  to 
cover  up  the  loops  if  practicable  ;  the  loops  should  be 
placed  as  near  the  base  of  the  teeth  as  possible,  the  cel- 
luloid forming,  when  finished,  a  part  of  that  "general 
concave  shape  which  is  desirable  in  upper  dentures,  and 
which  is  not  possible  to  obtain  with  the  ordinary  sol- 
dered work."  The  case  is  now  ready  to  be  flasked,  and 
should  be  treated  as  an  ordinary  denture  to  the  finish- 
ing process. 


102  DENTAL    PROSTHESIS   AND    METALLURGY. 

ARTIFICIAL    DENTURES 

CONSTRUCTED  BY  THE  SWAGING  PROCESS. 

Forming  the  Dies  and  Counter-Dies. — From 
the  various  methods  which  have  been  adopted,  we  will 
here  consider  only  the  one  which  has  proven  the  most 
satisfactory  and  is  most  generally  used.  It  consists  in 
pouring  melted  metal  into  a  mold,  made  in  sand  or 
marble  dust,  from  a  plaster  cast.  After  the  die  is  thus 
secured,  the  counter-die  is  obtained  by  pouring  metal 
which  melts  at  a  lower  temperature  than  that  of  which 
the  die  is  made,  upon  it. 

Materials  for  Molding. — As  we  have  stated,  either 
sand  or  marble  dust  is  usually  employed  for  making 
molds.  Marble  dust  absorbs  sufficient  moisture  from 
the  atmosphere  to  render  it  cohesive,  which  gives  it  the 
advantage  of  being  always  ready  for  use ;  it  is  also  more 
cleanly  to  handle  than  sand,  and  gives  a  very  smooth 
and  uniform  surface  to  the  die.  When  sand  is  used  it 
should  be  very  fine,  such  as  is  used  by  brass  founders. 

It  should  be  mixed  with  just  sufficient  water  to  render 
its  particles  thoroughly  adherent.  An  excess  of  water 
should  be  avoided,  as  the  vapor  formed  by  the  molten 
metal,  when  it  is  poured  into  the  mold,  will  displace 
portions  of  the  sand  and  form  cavities  or  blisters  upon 
the  face  of  the  die ;  nor  should  the  sand  be  used  too 
dry,  as  in  that  case  it  will  crumble  away  in  detaching 
the  plaster  model. 

Oil  is  becoming  quite  popular  as  a  substitute  for  water 


ARTIFICIAL    DENTURES. 


103 


in  molding.  Sand,  when  mixed  with  oil,  has  the  ad- 
vantage of  always  being  in  readiness  for  use.  It  should 
be  used  in  about  the  proportion  of  one  quart  of  oil  to 
a  peck  of  sand. 

Preparing  the  Plaster  Cast  for  Molding. — 
After  the  cast  has  been  secured,  the  outline  of  the  plate, 
and  the  position  of  the  vacuum-chamber  and  clasps, 
when  used,  should  be  distinctly  marked  with  a  pencil. 
In  upper  cases,  whether  partial  or  full,  a  shallow  groove 
should  be  made  along  the  posterior  plate  line,  so  that 
when  the  plate  is  swaged  this  edge  will  press  firmly 
against  the  roof  of  the  mouth,  which  will  add  to  the 
adhesion  of  the  plate,  make  the  edge  less  perceptible  to 
the  tongue,  and  prevent  the  entrance  of  the  secretions 
and  food.  The  cast  should  also  be  carved  at  the  points 
where  the  integument  of  the  palate  is  soft  and  yielding. 
In  some  cases,  the  center  of  the  palatal  portion  of  the 
mouth  is  unusually  hard  and  unyielding,  in  fact,  large, 
bony  prominences  are  sometimes  found ;  these  points 
should  be  noted  when  the  impression  is  taken  ;  then, 
before  making  the  die,  a  slight  coating  of  wax  should 
be  placed  over  the  corresponding  parts  of  the  cast,  so 
as  to  relieve  the  pressure  at  this  point,  which  pressure 
would  otherwise  cause  rocking  of  the  plate,  thus  inter- 
fering with  its  adhesion  and  the  wearer's  comfort. 

Method  of  Making  the  Mold. — When  the  ma- 
terial has  been  selected  and  prepared,  and  the  model 
trimmed  and  carved  where  needed,  it  should  be  given 
a  coat  of  varnish  or  oil,  or,  what  is  still  better, 
covered  with  lycopodium  and  then  thoroughly  brushed 


104  DENTAL   PROSTHESIS    AND    METALLURGY. 

with  a  jeweler's  brush  or  soft  brush-wheel;  it  should 
then  be  placed  face  uppermost  on  the  molding  board  or 
table,  and  surrounded  with  a  metallic  molding  ring. 
The  molding  material  should  then  be  packed  closely 
and  firmly  around  and  over  the  cast  until  the  ring  is 
evenly  filled.  Considerable  care  should  be  observed  in 
manipulating  the  molding  material  when  packing.  If  it 
is  too  compact,  the  vapor  formed  in  pouring  the  hot 
metal  will  not  be  able  to  pass  out  readily,  and  may  cause 
imperfections  in  the  face  of  the  die;  and,  again,  where 
it  is  too  loosely  packed  the  fluid  metal  will,  to  some 
extent,  permeate  the  pores  and  render  the  face  of  the 
die  rough  and  imperfect. 

Level  off  the  surface  of  the  sand  with  a  wooden  rule, 
lift  the  flask  or  ring  with  its  contents  from  the  bench, 
turn  it  over  carefully,  and  lay  it  down  with  the  bottom 
of  the  cast  up.  Now  run  the  point  of  a  knife  or  spatula, 
held  at  an  angle  of  about  400,  all  round  the  cast,  so  as 
to  make  a  bevel  in  the  edge  of  the  sand.  Next  press 
the  sand  around  the  cast  firmly  with  the  fingers,  then 
brush  away  any  loose  particles  that  may  remain,  that 
none  may  fall  into  the  mold  when  the  cast  is  withdrawn. 
The  point  of  an  ordinary  tack  or  pin,  or  the  small  blade 
of  a  knife,  should  now  be  carefully  driven  into  the  center 
of  the  cast  by  a  few  gentle  taps  from  the  hammer. 
Grasp  the  head  of  this  firmly  between  the  thumb  and 
fingers,  and  with  a  small  hammer  distribute  a  few  gentle 
taps  over  the  surface  of  the  cast.  If  the  cast  cannot 
then  be  withdrawn,  continue  the  process,  and  at  the 
same  time  distribute  a  few  light  blows  over  the  edge  of 


ARTIFICIAL    DENTURES.  I05 

the  molding  ring,  when  it  will  usually  be  found  that 
the  cast  can  be  readily  lifted  out. 

All  these  manipulations  must  be  very  gentle,  or  the 
cast  may  be  tilted  or  rocked  in  the  sand,  and  thus  make 
a  false  impression. 

Another  method  of  removing  the  cast  from  the  sand, 
practiced  by  many  and  as  usually  given  in  the  text- 
books, is  to  re-invert  the  ring  and  contents,  hold  it 
above  the  table,  and  dislodge  the  cast  by  tapping  it 
gently  underneath.  It  is  self-evident,  however,  that 
the  former  is  the  better  method.  We  should  in  nearly 
all  cases  reject  a  mold  from  which  the  cast  had  fallen 
out  by  its  own  weight. 

The  "Hawes"  or  Sectional  Molding  Flask. 
— It  frequently  happens  that  the  case  in  hand  presents 
such  decided  undercuts  that  it  will  be  impossible  to 
obtain  a  correct  mold  in  the  manner  just  described,  as 
the  sand  would  become  impacted  in  these  depressions 
and  be  broken  away  with  the  model  when  it  is  dislodged. 
This  can  be  readily  overcome  by  employing  the  sec- 
tional molding  flask  invented  by  Dr.  G.  W.  Hawes.  It 
is  composed  of  two  sections  or  rings.  The  lower  ring 
is  composed  of  three  movable  pieces,  with  large  exten- 
sions which  project  toward  the  center  as  represented  in 
Fig.  41.  When  in  use  these  pieces  are  kept  in  place  by 
passing  pins  through  the  joints.  The  cast  should  now 
be  placed  inside  of  this  ring;  the  portion  representing 
the  alveolar  ridge  should  extend  slightly  above  the  top 
of  the  ring,  as  shown  in  Fig.  42.  The  sand  should  now 
be  packed  in  around  the  cast  to  a  level  with  the  most 


io6 


DENTAL    PROSTHESIS    AND    METALLURGY. 


prominent  points  on  the  outside  of  the  ridge.  The 
surface  of  the  sand  should  be  finished  smoothly,  de- 
scending slightly  toward  the  model,  so  as  to  form  a 
thick  edge  of  sand  for  the  more  perfect  parting  of  the 
flask.  Very  finely  pulverized  charcoal  should  now  be 
sifted  over  the  exposed  surface  of  the  sand,  to  prevent 


Fig.  41. 


Fig.  42. 


the  next  portion  contained  in  the  upper  section  from 
adhering.  The  plain  ring- (Fig.  41)  is  then  placed  in 
position  and  filled  with  sand,  which  should  be  well 
packed  over  the  face  of  the  cast. 

The  upper  ring  is  now  carefully  lifted  from  the  lower 
one,  which  may  then  be  parted  by  removing  the  long 


ARTIFICIAL    DENTURES.  107 

pin,  when  the  cast  should  be  taken  away.  The  ring 
may  be  again  closed  and  fastened  by  replacing  the  pin  ; 
the  upper  section  is  then  readjusted,  and  the  entire 
flask  inverted,  when,  if  the  process  has  been  accurately 
conducted,  the  mold  will  be  found  perfect. 

Forming  Pattern  for  Plate.  —  Having  deter- 
mined upon  the  proper  form  and  dimensions  of  the 
plate  for  any  given  case,  its  outlines  should  first  be 

Fig.  43. 


traced  upon  the  model  with  a  pencil ;  from  this  an  exact 
pattern  in  lead-  or  tin-foil  may  be  obtained ;  in  partial 
cases  the  pattern  may  be  sufficiently  ample  to  partially 
overlap  the  cut  extremities  of  the  teeth,  which  have 
been  previously  cut  from  the  model,  as  shown  in  Fig.  43. 
The  outlines  of  the  pattern  are  then  traced  upon  the 
plate  of  gold  or  other  metal  used  for  the  base.  The 
redundant  portions  of  plate  are  then  cut  away  with 
plate  shears  and  forceps,  and  the  edges  trimmed  smooth 
with  a  file.     A  very  convenient  and  almost  indispensable 


io8 


DENTAL    PROSTHESIS   AND    METALLURGY. 


instrument  for  cutting  away  the  plate  in  conformity  with 
the  palatal  curvatures  of  the  teeth  is  the  plate  forceps, 
exhibited  in  Fig.  44. 

Swaging  the  Plates. — The  plate  cut  to  the  proper 
form  is  now  annealed,  then  placed  upon  the  die,  and,  if 
for  a  full  upper  denture,  or  in  a  partial  where  the  plate 
is  to  extend  over  the  alveolar  ridge,  it  is  brought 
as   nearly   as   possible  into  adaptation  with  No.  1  of 

Fig.  44. 


the  " progressive  counter-dies,"*  which  is  then  fol- 
lowed with  Nos.  2  and  3.  The  two  metallic  pieces — 
that  is,  the  die  and  counter-die — are  brought  forcibly 
together  with  a  few  steady  and  well-directed  blows 
from  a  heavy  hammer.  Tilting  of  the  die,  resulting 
sometimes  from  a  one-sided  blow,  may  be  obviated 
by  placing  a  cone-shaped  piece  of  cast-iron,  brass, 
or  zinc  over    the   die,  the    base  of   the  cone    resting 


*See  Richardson's  "Mechanical  Dentistry,"  6th  Ed.,  page  178. 


ARTIFICIAL    DENTURES.  I09 

on  the  back  of  the  die;  by  this  expedient  the  force  of 
the  blow  is  equalized  and  concentrated  more  directly 
over  the  die.  If,  in  the  process  of  stamping,  any  por- 
tion of  the  plate  is  found  cracking  or  parting,  its 
further  extension  at  that  point  may  be  prevented  by 
flowing  a  little  solder,  as  near  the  crack  of  the  plate  as 
possible  at  the  termination  of  the  fissure. 

Annealing  the  Plate. — During  the  progress  of 
swaging,  the  plate  should  be  frequently  annealed,  which 
is  done  by  bringing  it  to  a  full  red  heat  under  the  blow- 
pipe ;  the  plate  is  thus  rendered  more  pliant  and  can  be 
more  readily  and  perfectly  forced  into  adaptation  to  the 
irregularities  on  the  face  of  the  die. 

It  is  better  in  all  cases  to  have  duplicate  copies  both 
of  the  die  and  the  No.  3  counter-die  in  reserve  with 
which  to  complete  the  swaging,  inasmuch  as  more  or 
less  deformity  of  both  swages  unavoidably  occurs  before 
the  plate  is  brought  into  very  accurate  coaptation  with 
the  die.  The  stamping  conducted  thus  far,  the  plate 
may  be  applied  to  the  plaster  model,  and  if  found  too 
full  at  any  point,  it  should  be  trimmed  with  the  plate 
forceps  and  file  to  the  exact  dimensions  required. 

In  partial  cases,  the  margins  of  the  plate  adjoining 
the  necks  of  the  teeth  should  be  permitted  either  to  lie 
closely  to  them,  or  should  be  cut  away,  leaving  a  space 
equal  to  a  line  or  more  between  the  plate  and  the  teeth  ; 
for  if  but  a  very  narrow  line  of  uncovered  gum  remains 
at  these  points,  injury  to  the  parts  immediately  surround- 
ing the  necks  of  the  teeth  is  more  liable  to  occur  from 
strangulation  of  the  interposed  gum  than  if  the  plate 


IIO  DENTAL   PROSTHESIS   AND    METALLURGY. 

were  further  removed  from  the  teeth  or  rested  directly 
against  them. 

If  the  portion  of  the  plate  which  passes  in  between  the 
remaining  teeth  is  quite  narrow,  as  where  but  a  single 
tooth  is  to  be  supplied,  it  should  be  strengthened  by 
doubling  the  plate  at  such  a  point.  It  is  also  advisable 
in  many  cases,  in  order  to  provide  more  perfectly 
against  fracture  or  distortion  of  the  base  in  mastication, 
to  wire  or  double  the  entire  border  of  the  plate  adjoining 
the  necks  of  the  teeth. 

The  edges  of  those  parts  of  the  plate  occupying  the 
vacuities  on  the  ridge  should  be  filed  thin  to  admit  of  a 
more  accurate  adaptation  of  the  artificial  with  the 
natural  gum,  and  should  not,  ordinarily,  extend  beyond 
the  outer  circle  of  the  contiguous  teeth,  allowing  the 
gum  extremity  of  the  artificial  tooth  to  overlap  and  rest 
directly  on  the  natural  gum  above.  If,  however,  the 
concavity  between  and  above  the  teeth  on  the  external 
border  of  the  ridge  is  considerable,  the  interdentinal 
portions  of  plate  should  overlap  the  border  completely 
and  underlie  the  porcelain  gum. 

Adjusting  Clasps  to  the  Plate. — Having  pro- 
ceeded thus  far  in  the  operation,  the  plate  and  clasps, 
when  the  latter  are  to  be  employed,  should  next  be 
united  to  each  other,  and  the  utility  and  comfort  of  the 
appliance  in  the  mouth,  as  well  as  the  safety  of  the 
natural  organs  used  for  the  purpose  of  support,  will 
depend  in  a  great  measure  upon  the  accurateness  of  the 
relation  of  the  several  parts  of  the  appliance  to  the 
organs   of    the    mouth ;    it  being  a  matter  of  primary 


ARTIFICIAL    DENTURES.  Ill 

importance  that  the  various  parts  of  the  substitute  should 
be  so  adjusted  to  the  remaining  teeth — especially  those 
to  which  the  clasps  are  applied — and  the  ridge  and 
palate,  that  it  shall  not,  in  any  material  degree,  act  as  a 
retractor  upon  the  organs  of  support,  or  furnish  inter- 
spaces for  the  lodgment  of  food,  while  at  the  same  time 
it  should  be  so  fitted  as  to  easily  be  removed  and  applied 
by  the  patient. 

Manner  of  Securing  Clasps  to  the  Plate. — The 
clasps  having  been  fitted  to  the  plaster  teeth  and  the 
base  swaged  to  the  form  of  the  palatal  arch  and  ridge, 
the  clasps  are  adjusted  to  the  teeth  in  the  mouth,  the 
plate  is  placed  in  its  proper  position,  and  an  impression 
in  plaster- of- Paris  taken  of  the  latter  with  all  in  place; 
plaster  is  recommended,  as  with  it  we  can  secure  more 
accurately  the  relative  adjustment  of  the  several  parts 
than  with  any  other  material.  The  impression,  with  the 
plate  and  clasp  adhering,  is  then  removed  from  the 
mouth,  its  surface  oiled,  and  a  model  obtained  in  the 
ordinary  manner.  If,  in  separating  the  model  and 
impression,  the  plate  adheres  to  the  latter,  it  should  be 
detached  and  adjusted  to  the  model  and  the  clasps 
arranged  upon  the  plaster  teeth.  The  plate  and  clasps 
may  now  be  attached  to  each  other  temporarily,  with 
adhesive  wax,  in  the  relation  they  occupy  on  the  model, 
and  then  removed  carefully  and  the  clasps  and  palatal 
face  of  the  plate  embedded  in  a  mixture  of  nearly  equal 
parts  of  plaster,  sand,  and  asbestos.  Before  uniting  the 
two  pieces  on  the  model  with  wax,  however,  the  ends  of 
the  clasps  should  be  slightly  spread  apart,  in  order  that 


112  DENTAL    PROSTHESIS   AND    METALLURGY. 

they  may  part  readily  from  the  plaster  teeth,  without,  in 
any  degree,  changing  their  exact  relation  to  the  plate ; 
in  doing  which,  it  should  be  observed  that  all  parts  of  the 
clasps  which  are  to  be  united  to  the  plate  should  remain 
in  close  contact  with  the  plaster  teeth.  After  invest- 
ment, in  which  the  plate  and  clasps  are  embedded,  has 
become  sufficiently  hard,  the  portions  of  wax  which 
temporarily  united  the  latter  should  be  removed,  and  the 
surfaces  of  the  clasps  and  plate,  where  they  unite  with 
each  other,  coated  with  borax  ground  in  water  to  the 
consistency  of  cream ;  small  pieces  of  solder  are  then 
placed  along  the  lines  of  contact,  the  investment  heated 
in  a  furnace  until  the  plate  acquires  a  full  red  heat,  when 
it  is  removed,  placed  upon  a  suitable  holder,  and  the 
solder  fused  with  the  blowpipe. 

Another  method  consists  in  securing  the  proper  rela- 
tion of  the  clasps  to  the  teeth  in  the  mouth  by  the  use, 
in  the  first  instance,  of  what  are  termed  "  temporary 
fastenings."  The  plate  and  clasps  are  first  applied  as 
accurately  as  possible  to  the  model,  and  are  then  con- 
nected by  a  narrow  strip  of  plate  or  piece  of  wire  bent 
in  the  form  of  a  bow,  the  concavity  facing  the  model, 
one  end  of  which  is  lightly  soldered  to  the  palatal  side 
of  the  clasp,  and  the  other  to  a  contiguous  point  upon 
the  plate,  as  exhibited  in  Fig.  45,  and  the  pieces  thus 
temporarily  united  are  removed  from  the  model  and 
adjusted  to  the  parts  in  the  mouth.  If  the  position  of 
the  clasps  is  found  in  any  respects  faulty,  they  can  be 
easily  and  accurately  adapted  to  the  walls  of  the  teeth 
by  bending   or  twisting   the  connecting   strip    in  any 


ARTIFICIAL    DENTURES. 


IJ3 


desired  direction  with  pliers  or  other  instruments  suit- 
able for  the  purpose.  This  accomplished,  the  plate  and 
clasps  are  removed,  and  the  operation  of  permanently 
uniting  the  clasps  to  the  plate  performed  in  the  usual 
manner.* 

Atmospheric    Pressure     or    Adhesion   as    a 
Means  of  Support. — The  method  of  attaching  par- 

Fig.  45. 


tial  sets  of  teeth  to  the  superior  jaw  by  means  of  atmos- 
pheric pressure,  or  by  adhesion,  is  more  generally  prac- 
ticed than  formerly,  and  whenever  the  condition  of  the 
soft  parts  of  the  mouth,  the  general  configuration  of  the 
palatal  arch,  and  the  antagonism  or  occlusion  of  the 


*  For  an  elaboration  upon  this  subject,  see  Richardson's  "  Me- 
chanical Dentistry,"  6th  Edition. 


H4 


DENTAL    PROSTHESIS    AND    METALLURGY. 


artificial  with  the  natural  teeth  favor  its  adoption,  these 
forces  should,  in  all  practical  cases,  be  utilized  in 
preference  to  the  use  of  clasps  for  purposes  of  attach- 
ment. 

The  general  form  of   the  base,   where  several  teeth 
scattered  throughout  the  arch  are  required,  is  shown  in 

•     Fig.  46. 


Fig.  46.  In  most  cases,  whether  one  or  a  greater  num- 
ber of  teeth  are  to  be  replaced,  increased  adherence 
and  stability  of  the  substitute  will  be  better  secured  by- 
permitting  the  plate  to  cover  the  larger  portion  of  the 
roof  of  the  mouth  \  though,  in  cases  that  present  the 
best  form  of  the  vault,  a  diminished  surface  may  be  given 
to  the  base  with  equally  satisfactory  results. 


ARTIFICIAL   DENTURES.  115 

Manner  of  Forming  the  Vacuum  Chamber. — 

Where  a  central  cavity,  or  "Air  Chamber"  is  to  be 
stamped  into  the  base,  the  model  should  be  prepared  for 
the  purpose  before  molding.  Fig.  46  shows  its  general 
form  and  position.  The  model  may  be  prepared  in 
either  of  the  following  ways:  1.  The  form  of  the  chamber 
may  be  cut  from  the  wax  or  plaster  impression,  in 
which  case  the  plaster  will  be  raised  at  a  correspond- 
ing point  or  points  upon  the  model,  and  will  have 
exactly  the  same  form  and  depth  as  the  cavity  in  the 
impression.  2.  Cover  the  palatal  face  of  the  model 
with  a  sheet  of  wax  equal  in  thickness  to  the  required 
depth  of  the  chamber,  and  cut  out  from  this,  at  the 
desired  point,  the  form  of  the  cavity ;  fill  the  latter  with 
plaster,  and  when  hard  remove  the  wax  and  trim  the 
raised  portion  to  the  proper  form.  3.  Cut  a  pattern  of 
the  required  form  and  depth  of  chamber  from  a  sheet  of 
wax  or  lead ;  place  it  in  the  proper  position  in  the  arch, 
and  press  it  down  with  the  fingers  or  burnisher  until  it 
conforms  to  the  contour  of  the  palate ;  it  is  then  fixed 
in  place  either  by  confining  it  with  a  small  pin  or  tack 
driven  through  it  into  the  plaster,  or  by  interposing 
softened  wax  or  other  adhesive  material  between  the 
pattern  and  model. 

The  metallic  swages  being  secured,  the  plate  is  inter- 
posed between  them  and  swaged  until  it  conforms 
perfectly  to  the  face  of  the  die.  During  the  operation 
the  plate  should  be  frequently  annealed  as  previously 
described. 

The  Use  of  a  Tracer. — Unless  the  plate  used  is 


Il6  DENTAL    PROSTHESIS   AND    METALLURGY. 

purer  and  thinner  than  is  generally  employed,  or  than 
is  consistent  with  the  required  strength,  it  will  fail  to 
be  forced  perfectly  into  the  groove  around  the  chamber 
by  the  process  of  swaging  alone;  a  more  definite 
border,  however,  may  be  formed  by  forcing  the  plate 
in  at  this  place  with  a  small,  smooth-faced  stamp  or 
tracer,  shaped  to  the  angle  of  the  groove,  passing  it 
round  the  chamber  and  with  a  small  hammer  carefully 
forcing  the  plate  in  until  a  somewhat  sharp  and  abrupt 
angle  is  obtained  to  the  palatal  edge  of  the  chamber. 
After  the  chamber  is  as  perfectly  formed  as  possible  in 
this  way,  the  plate  should  be  well  annealed  and  again 
swaged  to  correct  any  partial  deformity  occasioned  by 
stamping  the  chamber. 

The  Soldered  "Air  Chamber."— A  still  more 
perfectly  defined  angle  may  be  given  to  the  borders  of 
the  chamber  in  the  following  manner :  After  swaging 
the  plate  sufficiently  to  indicate  the  exact  position  and 
form  of  the  chamber,  the  portion  forming  the  latter 
should  be  separated  from  the  main  plate  by  completely 
dividing  it  with  a  saw,  or  small,  sharp,  chisel-shaped 
instrument,  cutting  on  a  line  with  the  groove  around 
the  chamber  until  the  latter  is  entirely  separated.  The 
cut  portion  of  the  main  plate  is  then  trimmed  evenly 
with  a  file,  being  careful  not  to  enlarge  the  opening 
more  than  is  required  to  remove  the  irregularities  of  the 
edge  formed  in  cutting.  The  plate,  with  its  central 
portion  removed,  is  then  placed  upon  the  die,  when  a 
separate  piece  of  gold  cut  to  the  general  form  of  a 
chamber,  but  somewhat  larger  than  the  opening  in  the 


ARTIFICIAL    DENTURES.  117 

main  plate,  is  adjusted  over  the  chamber,  and  struck  up 
with  the  plate  until  the  overlapping  portions  of  the 
central  piece  are  forced  down  upon  the  plate  around 
the  margins  of  the  chamber.  It  is  not,  however,  always 
necessary  to  employ  a  separate  piece  of  gold  for  the 
chamber,  as  the  central  portion  cut  from  the  plate  in 
the  first  instance  may  be  sufficiently  enlarged  for  the 
purpose.  This  is  accomplished  by  first  flattening  out 
the  detached  portion,  annealing  it,  and  then  passing 
successive  portions  of  its  edges  a  sixteenth  of  an  inch 
or  more  between  the  rollers,  the  latter  being  sufficiently 
approximated  to  produce  a  perceptible  thinning  of  the 
margins.  When  the  entire  border  of  the  chamber  piece 
has  been  thus  extended,  it  will  be  found  so  much  en- 
larged that,  when  adjusted  to  the  die  and  swaged  in 
connection  with  the  main  plate,  its  borders  will  overlap 
and  rest  upon  the  margins  of  the  opening  in  the  base, 
as  in  the  other  case. 

The  portions  of  the  plate  and  cut  chamber  lying,  in 
contact  are  now  coated  with  borax  and  small  pieces  of 
solder  placed  along  the  line  of  union  on  the  lingual  side 
of  the  plate,  when  the  two  pieces,  being  transferred  to 
the  soldering  block,  are  permanently  united  by  flowing 
the  solder  with  a  blowpipe.  Sufficient  heat  should  be 
applied  to  induce  an  extension  of  the  solder  between 
the  two  portions  of  plate,  filling  up  completely  the  gap 
between  them  to  the  edge  of  the  orifice  in  the  main 
plate,  forming,  at  this  point,  a  square  and  well-defined 
angle  to  the  margins  of  the  chamber. 

Having  constructed  the  base  to  be  used  as  a  support 


Il8  DENTAL    PROSTHESIS   AND    METALLURGY. 

for  the  artificial  teeth,  it  is  necessary,  before  arranging 
the  teeth  on  the  plate,  to  i.  Secure  an  accurate  repre- 
sentation of  all  the  antagonizing  natural  teeth.  2.  If  it 
is  a  partial  denture,  the  plate  should  now  be  properly 
adjusted  to  the  mouth,  and  an  impression  taken  with  it 
in  position,  bringing  the  plate  away  in  the  impression; 
into  this  a  plaster  cast  should  be  run,  which  upon  being 
separated  from  the  impression  will  give  an  accurate 
representation  of  the  remaining  natural  teeth,  with  the 
position  of  the  plate  and  its  relation  to  these  teeth.  3. 
If  there  are  enough  teeth  remaining  that  articulate  with 
antagonizing  teeth  to  act  as  an  accurate  guide,  the  two 
casts  may  now  be  adjusted  and  secured  in  an  articula- 
tor. If,  however,  this  cannot  be  done  with  any  degree 
of  accuracy,  the  plate  should  be  removed  from  the  cast, 
a  rim  of  softened  wax  placed  upon  it  at  the  several 
points  where  the  teeth  are  missing.  The  plate  with 
the  wax  attached  is  now  placed  in  the  mouth  and  the 
"  bite  "  taken  in  the  ordinary  manner.*  4.  If  the  case 
in  hand  should  be  a  full  denture,  upper  or  lower,  the 
articulation  or  bite  is  in  every  particular  taken  in  the 
usual  way,  except  that  the  swaged  plate  is  used,  instead 
of  the  temporary  base  plate,  to  support  the  wax  rim. 

Full  Lower  Base. — If  the  lower  plate  is  con- 
structed from  a  single  lamina  of  gold  or  other  metal,  it 
should  be  somewhat  thicker  (about  No.  24)  than  that 
used  in  upper  cases,  and  should  also  be  of  finer  quality, 


*  See   chapter    on    "  Taking    the    Bite    and   Antagonizing   the 
Models." 


ARTIFICIAL    DENTURES.  II9 

as  the  additional  thickness  of  the  plate  and  the  peculiar 
form  of  the  inferior  maxilla  render  a  greater  degree  of 
pliancy  necessary  in  swaging  it  to  the  form  of  the  ridge. 
The  general  form  of  a  base  for  an  entire  lower  denture 
is  exhibited  in  Fig.  47.  The  internal  border  of  this 
plate  should  usually  be  doubled,  either  by  turning  the 
edge  over  in  swaging,  or  by  soldering  on  a  narrow  strip 
of  plate  or  half-round  wire. 

Fig.  47.  Fig. 48. 


Reinforcing. — To  secure  a  more  perfect  adaptation 
of  the  plate  to  the  ridge,  the  use  of  a  double  instead  of 
a  single  plate  throughout,  in  which  case  a  thin  plate, 
No.  30  of  the  gauge,  should  be  swaged  to  the  form  of 
the  ridge  in  the  first  instance,  and  then  a  duplicate 
plate,  swaging  the  two  together  and  uniting  them  to 
each  other  with  solder.  A  plate  of  the  specified  thick- 
ness may  be  very  readily  and  accurately  swaged  to  any 
irregularities  in  the  ridge,  and  when  the  two  are  united 
the  base  will  be  heavier  and  stronger  than   a  single 


120  DENTAL    PROSTHESIS    AND    METALLURGY. 

lamina  of  the  ordinary  thickness.  Instead,  however,  of 
doubling  the  entire  plate,  it  will  be  sufficient,  in  most 
cases,  to  adapt  the  second  plate  only  to  the  lingual  sur- 
face of  the  first,  extending  it  up  from  the  lower  edge  to 
a  point  corresponding  as  nearly  as  possible  with  the 
inner  portions  of  the  base  of  the  teeth  when  the  latter 
are  adjusted  to  the  plate.  See  Fig.  48.  A  moderately 
thin  plate  may,  in  this  manner,  be  used  for  the  primary 
base,  while  the  duplicate  band  will  impart  the  desired 
strength  to  the  plate.  In  adopting  either  of  these 
methods  the  plates,  after  they  are  united  to  each  other 
with  solder,  should  be  again  swaged  to  correct  any 
change  of  form  which  may  take  place  during  the  solder- 
ing process. 

Partial  Lower  Base. — To  avoid  encroaching  upon 
the  reflected  portion  of  the  mucous  membrane,  the 
glands  beneath  the  tongue,  or  the  frenum  linguae,  it  is 
necessary  to  make  the  lingual  surface  of  the  anterior 
portion  of  the  palate  quite  narrow,  which,  of  course,  in 
partial  cases,  weakens  the  plate  at  this  point.  It  is, 
therefore,  desirable — even  though  the  ordinary  thick- 
ness of  metal  has  been  used — to  reinforce  or  double 
this  connecting  band,  the  duplicate  piece  extending 
back  over  the  lateral  wings  of  the  plate,  and  crossing 
them  obliquely  as  indicated  in  Fig.  49. 

After  this  has  been  accomplished  and  the  plate  care- 
fully fitted  to  the  mouth,  the  "bite,"  antagonizing 
model,  etc.,  are  secured  in  the  manner  previously  de- 
scribed. 

Grinding  and  Adjusting  the  Teeth. — In  arrang- 


ARTIFICIAL    DENTURES.  121 

ing  or  adjusting  single  gum  teeth  to  the  plate,  the  por- 
tions applied  to  the  base  should  be  ground  away  just 
sufficiently  to  restore  the  required  fulness  of  the  parts 
and  to  give  proper  length  and  inclination  to  the  teeth. 
The  coaptation  of  the  ground  surface  of  the  teeth  to  the 
plate  should  be  as  accurate  as  possible,  so  as  to  exclude 
particles  of  food,  and  to  furnish  such  a  basis  to  each 

Fig.  49. 


tooth  as  will  provide  most  effectually  against  fracture 
when  acted  upon  by  the  forces  applied  to  them  in  the 
mouth.  The  gum  extremities  of  the  teeth  should  also 
be  accurately  jointed,  by  grinding  carefully  from  their 
proximate  edges  until  the  joints  will  be  rendered  incapa- 
ble of  ready  detection  in  the  mouth,  care  being  taken 
that  this  coaptation  of  the  adjoining  surfaces  is  uniform, 
for  if  confined  to  the  outer  edge  alone  portions  of  the 
gum  enamel  may  be  broken  away  in  the  process  of  solder- 
9 


122  DENTAL    PROSTHESIS    AND    METALLURGY. 

ing.  There  are  cases  of  a  mixed  character  that  render 
it  more  difficult  to  effect  a  harmonious  and  symmetrical 
arrangement  of  the  teeth,  as  where  a  limited  number  of 
the  natural  teeth  at  intervals  have  been  long  absent,  and 
the  excavations  in  the  ridge  consequent  on  absorption 
alternate  with  other  points  upon  the  ridge  in  a  com- 
paratively unchanged  condition.  To  give  uniformity 
to  the  denture  by  restoring  perfectly  the  required  circle 
of  the  arch  in  such  cases  will  necessitate  the  employ- 
ment of  plain  and  single  gum  teeth  conjointly.  When- 
ever necessary,  those  portions  of  the  base  occupied  by 
the  plate  teeth  may  be  cut  away  in  such  a  manner  as  to 
permit  the  latter  to  be  adjusted  directly  to  the  unab- 
sorbed  gum. 

Arranging  the  Teeth  for  a  Full  Upper  and 
Lower  Denture. — In  the  process  of  grinding  the 
teeth  to  the  base,  above  and  below,  the  operator  should 
commence  by  first  arranging  the  superior  central  inci- 
sors, and  then  pass  back  from  tooth  to  tooth,  grind  and 
adjust,  until  the  entire  upper  set  is  arranged.  The 
superior  central  incisors  should  be  placed  parallel  with 
each  other,  but  the  cutting  edges  of  the  laterals  and  the 
points  of  the  cuspids  should  incline  slightly  toward  the 
median  line  of  the  mouth.  The  anterior  six  may  be  made 
to  describe,  with  more  or  less  exactness,  the  segment  of 
a  circle,  but  a  somewhat  abrupt  angle  may  be  given  to 
the  arch  on  each  side  by  placing  the  first  bicuspid  within 
the  circle  in  such  a  way  that,  when  standing  directly  in 
front  of  the  patient  and  looking  into  the  mouth,  only 
a  narrow  line  of  the  exterior  face  of  the  crowns  of  these 


ARTIFICIAL    DENTURES.  I  23 

teeth  will  be  seen,  while  the  remaining  teeth  posterior 
to  them  should  be  arranged  nearly  on  a  straight  line, 
diverging  as  they  pass  backward.  When  arranged  in 
the  manner  described,  the  peripheral  outline  of  the  arch 
will  exhibit  somewhat  the  form  presented  in  the  accom- 
panying diagram  (Fig.  50). 

The  lower  teeth  should  now  be  arranged,  and  to  best 
accomplish  this,  the  bicuspids  should  first  be  adjusted, 

Fig.  50 


then  the  teeth  anterior  to  them  may  be  secured  in 
position,  and  lastly  the  molar  teeth  articulated.  In 
articulating  the  upper  and  lower  teeth,  the  normal 
occlusion  of  the  natural  organs  (which  is  described  in 
another  place)  should  be  imitated  as  nearly  as  the  other 
essential  requirements  of  the  case  will  admit. 

In  selecting  teeth  for  a  full  upper  denture  in  those 
cases  where  natural  teeth  are  remaining  below,  or  vice 
versa,  the  color,  size,  and  form   of  the  latter  will  serve 


124  DENTAL    PROSTHESIS   AND    METALLURGY. 

as  a  guide  in  the  choice  of  teeth  appropriate  for  the 
opposite  jaw.  In  fitting  and  arranging  the  teeth  upon 
the  base,  and  in  antagonizing  them  with  the  opposing 
natural  teeth,  the  same  general  principles  apply  as  those 
just  described  in  connection  with  full  upper  and  lower 
dentures. 

Having  adjusted  the  teeth  to  the  base,  they  should  be 
placed  in  the  mouth  before  uniting  them  permanently 
to  the  plate,  to  detect  and  remedy  any  error  of  arrange- 
ment either  in  respect  to  prominence,  position,  inclina- 
tion, length,  or  articulation. 

Manner  of  Forming  a  Rim  to  a  Plate. — If  the 
case  is  one  where  single  gum  or  block  teeth  are  em- 
ployed, and  it  is  intended  to  form  a  socket  or  groove 
upon  the  borders  of  the  plate  for  the  reception  of  the 
plate  extremities  of  the  teeth,  the  rim  forming  the  groove 
should  be  fitted  and  soldered  to  the  base  before  invest- 
ing the  piece  in  plaster.  If  the  alveolar  ridge  above  is 
shallow,  and  but  imperfectly  concealed  by  the  lip,  a  rim 
to  the  plate  will  be  inadmissible ;  as,  when  the  mouth 
is  opened  and  the  lip  retracted,  as  in  laughing,  the 
metallic  band  will  be  exposed  to  view.  A  rim  may  be 
fitted  and  attached  to  the  base  in  the  following  manner  : 
An  impression  in  plaster  is  first  taken  of  the  gum 
surfaces  of  the  teeth  and  exposed  border  of  the  plate ; 
but  as  it  will  be  impossible  to  detach  the  plaster  in 
perfect  condition  when  encircling  the  entire  arch,  or 
to  swage  perfectly  with  a  die  so  unfavorably  formed  for 
stamping,  separate  impressions  of  the  two  lateral  halves 
of  the  piece  should  be  taken  from  these  plaster  models, 


ARTIFICIAL    DENTURES;    SWAGING    PROCESS.         1 25 

and  from  the  latter,  dies  and  counter-dies  ;  with  these, 
two  strips  of  plate  of  sufficient  width  are  swaged,  each 
extending  from  the  heel  of  the  plate  to  a  little  beyond 
the  median  line  in  front,  overlapping  slightly  at  the 
latter  point.  The  portions  of  the  swaged  strips  embra- 
cing the  plate  ends  of  the  teeth  are  then  trimmed 
to  the  proper  width,  and  scalloped,  if  desired,  in 
correspondence  with  the  festoons  of  the  artificial 
gums.  In  whatever  way  the  rim  is  formed,  when  it 
has  been  fitted  to  the  plate  and  teeth  it  may  be  held 
temporarily  in  place  with  clamps  adjusted  at  two  or  three 
points  around  the  plate  and  then  transferred  to  a  piece 
of  charcoal,  and  secured  by  first  tacking  it  at  two  or 
three  points  with  solder.  The  groove  may  then  be  filled 
with  whiting,  mixed  with  water  or  alcohol,  to  prevent 
the  solder  from  flowing  in  and  filling  it  up ;  after  which 
small  pieces  of  solder  are  placed  along  the  line  of  union 
next  to  the  edge  of  the  plate,  and  the  rim  permanently 
united  throughout  with  the  blowpipe ;  after  which  the 
wax  and  teeth  are  reapplied  to  the  plate.* 

Investing. — The  plate,  with  the  wax  and  teeth  in 
place,  is  next  invested  preparatory  to  backing  the  teeth 
and  uniting  them  with  solder  to  the  base.  For  this 
purpose,  plaster  and  sand  in  equal  parts  may  be 
employed.  It  is  customary  to  incase  the  piece  in  the 
plaster  mixture  to  the  depth  of  from  one-half  to  three- 

*For  a  fuller  description,  see  Richardson's  Mechanical  Dentistry, 
6th  Edition. 


126  DENTAL   PROSTHESIS   AND    METALLURGY. 

fourths  of  an  inch,  leaving  only  the  lingual  surface  of 
the  plate  and  teeth  uncovered. 

Backing  the  Teeth. — The  plate  being  properly 
invested,  all  portions  of  the  wax  attached  to  the  inner 
surface  of  the  teeth  and  plate  should  be  thoroughly 
removed  with  suitable  instruments,  after  which  backings 
are  to  be  adjusted  to  the  teeth. 

A  plain  strip,  corresponding  in  width  with  the  tooth 
to  be  lined,  is  cut,  and  the  end  resting  on  the  main  plate 
conformed  accurately  with  the  file  to  the  irregularities 
on  the  surface  of  the  latter,  and  in  such  a  manner  as  to 
permit  the  strip  to  take  the  direction  of  the  tooth.  The 
general  form  of  the  stay  may,  in  the  first  place,  be 
obtained  by  cutting" a  strip  from  a  piece  of  gold  with  a 
pair  of  plate  forceps.  The  points  upon  the  stay  to  be 
pierced  for  the  admission  of  the  platinum  pins  may  be 
ascertained  by  coating  the  surface  of  the  former  with 
wax  softened  in  the  flame  of  a  spirit  lamp,  and  pressing 
it  first  against  the  lower  pin,  the  point  of  which  will  be 
indicated  by  an  indentation  of  the  wax.  The  backing 
is  then  perforated  at  this  point  with  a  plate  punch. 
The  strip  is  then  reapplied  to  the  upper  pin,  and  the 
second  hole  obtained  in  like  manner  as  the  first. 
Instead  of  using  wax,  the  ends  of  the  rivets  may  be 
stained  with  some  pigment,  which  will  show  the  points 
to  be  pierced  in  the  lining. 

The  backings  should  be  adapted  accurately  to  the 
back  of  the  tooth ;  it  is  then  cut  to  the  proper  length, 
reaching  nearly  or  quite  to  the  point,  and  shaped  with 


ARTIFICIAL   DENTURES;    SWAGING    PROCESS.         T27 

a  file  to  the  general  form  of  the  crown.  When  the 
stays  are  to  be  united  they  should  be  formed  with  a 
shoulder  at  a  point  corresponding  with  the  neck  of  the 
tooth,  and  the  proximate  edges  below  united  closely. 
The  process  of  soldering  will  be  greatly  facilitated  and 
the  piece  will  be  more  easily  and  artistically  finished  by 
securing,  in  the  first  instance,  a  perfect  coaptation  of 
all  the  parts  which  are  ultimately  to  be  united.  The 
sides  of  the  holes  in  the  backings  facing  the  plate 
should  now  be  enlarged  or  countersunk  with  a  spear- 
shaped  or  conical  bur  drill,  and  when  applied  to  the 
teeth  the  projecting  ends  of  the  platinum  pins  are  cut 
off  even  with  the  backings  and  then  split  and  spread 
apart  with  a  small,  chisel-shaped  instrument.  A  head  will 
thus  be  formed  to  the  rivets,  when  solder  is  fused  upon 
them,  which  will  prevent  them  from  drawing  from  the 
linings. 

The  Soldering  Process. — All  the  lines  of  union 
between  the  several  pieces  should  next  be  well  scraped, 
exposing  a  clean,  bright,  metallic  surface  to  the  solder; 
the  seams  are  then  coated  with  borax,  ground,  or  rubbed 
in  clean,  soft  water  to  about  the  consistency  of  cream  ;* 
after  which  small  pieces  of  solder  are  placed  along  the 
joints  and  over  the  points  of  the  platinum  pins.  The 
piece  thus  prepared  is  now  placed  in  the  furnace  or 

*  Slate  is  often  used  for  this  purpose,  but  is  unfit,  as,  in  rubbing 
the  borax,  loosened  particles  of  the  former  become  mixed  with  the 
latter  and  impede  the  flow  of  the  solder,  and  becoming  entangled 
render  it  unclean  and  porous.  Ground  glass  or  a  porcelain  slab  is 
the  best  for  the  purpose. 


128  DENTAL    PROSTHESIS    AND    METALLURGY. 

ordinary  fire-place  in  order  to  heat  the  entire  mass  pre- 
paratory to  soldering. 

The  heating  process  should  be  conducted  gradually 
until  the  case  acquires  a  visible  red  heat,  when  it  should 
be  removed,  placed  on  a  suitable  holder,  and  the  solder 
fused  with  the  blowpipe.  A  broad,  spreading  flame 
should  first  be  thrown  over  the  entire  surface  of  the 
plate  and  investment  until  the  temperature  of  the  entire 
mass  is  nearly  that  required  to  fuse  the  solder,  which  is 
indicated  by  the  latter  settling  and  contracting  upon 
itself;  the  flame  may  then  be  concentrated  upon  a  par- 
ticular point,  as  at  the  heel  of  the  plate  on  one  side, 
passing  around  from  tooth  to  tooth  until  all  the  parts 
are  completely  united  and  the  solder  is  well  and 
uniformly  diffused. 

Having  united  the  teeth  to  the  plate,  the  piece  may 
be  allowed  to  cool  gradually,  or  it  may  be  plunged  after 
the  lapse  of  a  few  minutes  into  boiling  water  without 
risk  of  injury  to  the  teeth.  When  cool,  the  plaster  is 
removed  and  the  plate  placed  in  the  acid  bath  (a  solu- 
tion of  equal  parts  of  sulphuric  acid  and  water),  where 
it  may  be  allowed  to  remain  until  the  discoloration  of 
the  plate  and  the  remains  of  the  vitrified  borax,  incident 
to  the  soldering,  are  removed,  or  it  may  be  put  into  a 
small  copper  vessel,  partly  filled  with  the  same  solution, 
and  boiled  for  a  few  minutes.  After  removing  the  plate 
from  the  acid,  it  should  be  boiled  for  five  minutes  in  a 
solution  of  chlorid  of  soda  or  common  salt  and  water 
to  remove  thoroughly  all  traces  of  the  acid. 

The  Finishing  Process. — Superfluous  portions  of 


ARTIFICIAL   DENTURES;    CASTING    PROCESS.  1 29 

solder  are  now  to  be  removed,  which  may  be  more 
quickly  accomplished  by  the  use  of  burs,  stones,  and 
discs  of  various  forms  and  sizes  attached  to  the  dental 
engine.  The  final  polish  may  then  be  given  by  the 
use,  first  of  crocus  and  then  rouge  applied  upon  a  French 
felt  wheel,  rapidly  revolved  upon  the  lathe. 


ARTIFICIAL  DENTURES  UPON  A  CAST 
METAL  BASE. 

The  method  of  constructing  artificial  dentures  upon 
a  cast  metal  base  has,  until  recently,  had  but  a  very 
limited  application. 

The  method,  as  commonly  practiced,  is  chiefly  applied 
to  lower  dentures  in  cases  where  unusual  absorption  of 
the  alveolar  ridge  has  taken  place,  requiring  increased 
weight  to  secure  sufficient  stability  of  the  substitute. 
The  alloys  employed  for  this  work  are  those  originally 
compounded  by  Drs.  Wood,  Watt,  and  Weston,  and 
are  known  upon  the  market  by  these  respective  names 
— as  Wood's,  Watt's,  or  Weston's  Metal. 

The  manipulations  concerned  in  this  method  are  pre- 
cisely the  same  as  for  rubber  work  up  to  the  flasking 
process,  except  in  forming  the  cast.  As  plaster-of-Paris 
alone  will  not  give  sufficient  strength,  either  to  the 
model  or  to  the  investment,  it  should  in  all  cases  be 
thoroughly  mixed  with  an  equal  part  of  either  marble- 
dust,  silex,  pumice-stone,  or  some  other  substance  which 
will  maintain  its  form  perfectly  under  the  heat  neces- 


13° 


DENTAL   PROSTHESIS    AND    METALLURGY. 


sarily  applied  in  thorough  drying   and  in  casting  the 
base. 

Flasking. — Assuming  that  the  teeth  have  been  pro- 
perly articulated  and  waxed  up,  the  case  is  now  ready 
for  the  flask.     One  of  the  best  adapted  flasks  for  casting 

Fig.  51. 


is  shown  in  Fig.  51.  The  piece  is  flasked  in  the  same 
manner  as  for  rubber  work,  except  that  the  investment 
material  used  should  be  the  same  as  that  employed  for 
the  cast.  After  the  investment  has  become  sufficiently 
hard,  the  sections  of  the  flask  are  separated,  grooves  or 
gateways  are  cut  from  the  posterior  margins  of  the 
mold  to  the  openings  shown  in  the  figure,  thus  provid- 


ARTIFICIAL   DENTURES;    CASTING    PROCESS.  131 

ing  for  the  pouring  of  the  molten  metal  upon  the  one 
side  and  the  escape  of  the  surplus  up  the  other ;  after 
which  all  traces  of  the  wax  should  be  removed  with 
boiling  water. 

The  mold  is  next  well  dried  by  exposing  it  to  an  oven 
heat  for  two  or  three  hours ;  the  sections  of  the  flask 
are  then  adjusted  to  each  other,  and  tightly  clamped  to 
prevent  the  escape  of  the  metal  when  poured.  Before 
bringing  the  alloy  to  the  fusing  point  (which  should 
always  be  done  in  a  clean  crucible),  the  mold  should  be 
tested  for  moisture.  This  is  done  by  holding  the  surface 
of  a  mirror  over  the  openings  in  the  flask ;  if  there  is  a 
trace  of  moisture  being  driven  off  it  will  be  shown  upon 
the  glass,  and  the  heat  should  be  continued  until  the 
case  is  completely  dried,  when  it  is  ready  for  casting. 

Pouring  the  Metal. — The  metal  should  now  be 
poured  into  the  mold  through  one  of  the  lateral  open- 
ings, and  it  should  rise  quickly  and  freely  into  the 
opposite  ones.  If  bubbling  should  occur,  which  will 
never  happen  if  the  cast  has  been  sufficiently  dried,  the 
flask  should  be  lightly  tapped  on  some  hard  surface  until 
the  ebullition  ceases,  thus  insuring  a  more  certain  in- 
trusion of  the  metal  into  all  parts  of  the  mold  before 
solidification  takes  place. 

The  Finishing  Process. — When  the  flask  is  quite 
cold,  the  plate  may  be  readily  removed  by  soaking  the 
investing  material  for  a  moment  in  water.  All  super- 
fluous metal  is  now  removed  with  suitable  scrapers,  files, 
and  sand-paper  or  emory  cloth,  and  the  final  polish 
given  with  the  brush-wheels,  pumice-stone,  and  whiting. 


132  DENTAL    PROSTHESIS    AND    METALLURGY. 

ARTIFICIAL    DENTURES    UPON    AN 
ELECTRO-DEPOSITED  BASE.* 

Deposition  of  Copper  by  the  Single-Cell 
Process. — The  simplest  form  of  arrangement  for  the 
deposition  of  metals,  either  for  artificial  dentures  or 
electrotyping  small  objects,  is  known  as  the  "single-cell" 
process.  This  form  of  battery  is  shown  in  Fig.  52. 
A  indicates  the  outer  jar ;  B,  the  porous  cup  or  cell, 
which  is  somewhat  taller  than  the  containing  vessel ; 
C,  the  zinc  (amalgamated),  which  is  made  from  a  strip 
of  sheet-zinc,  and  is  suspended  by  means  of  a  copper 
wire ;  while  D  represents  suspended  plaster  casts. 

Preparation  of  Solutions. — Make  a  saturated 
solution  of  copper  sulphate  (blue-stone)  by  dissolving 
crystals  of  that  substance  in  hot  water.  This  should 
always  be  of  sufficient  strength  to  have  a  few  of  the  crys- 
tals remain  suspended.  The  solution,  when  cold,  is 
poured  into  the  outer  jar.  The  solution  used  in  the 
porous  cup  or  cell  is  dilute  sulphuric  acid  (sulphuric  acid 
1  part,  water  10  parts),  which  should  stand  a  little  higher 
in  the  cell  than  that  in  the  outer  jar.  This  should  be 
replenished  about  every  24  hours  when  in  operation. 

Amalgamating  the  Zinc. — Thoroughly  cleanse  the 
zinc  by  washing  it  in  dilute  sulphuric  acid.  This  is  best 
accomplished  by  placing  the  zinc  in  a  dish,  pouring  a 

*  This  chapter  is  in  accordance  with  the  teachings  of  E.  A.  Kretsch- 
man,  Instructor  in  the  Electro-deposition  of  Metals,  in  Pennsyl- 
vania College  of  Dental  Surgery. 


ARTIFICIAL    DENTURES;    ELECTRO-DEPOSIT.         1 33 

small  quantity  of  the  acid  over  it,  then,  after  having  tied 
a  small  piece  of  flannel  over  the  end  of  a  stick,  proceed 
to  brush  the  acid  over  the  surface  of  the  metal ;  after 
which  pour  a  little  mercury  on  the  plate,  and,  with  a 
similar  little  mop,  rub  it  thoroughly  over  and  into  the 

Fig.  52. 


surface  of  the  zinc,  which  will  give  it  a  bright,  silvery 
luster. 

Preparation  of  the  Plaster  Cast. — Have  the 
cast  well  dried  ;  twist  around  it  a  piece  of  copper  wire, 
then  dip  in  melted  wax  and  allow  to  drain.  The  cast  is 
then  to  be  covered  with  finely  powdered  plumbago  by 
briskly  brushing  it  over  the  surface  with  a  soft  brush, 


134  DENTAL    PROSTHESIS    AND    METALLURGY. 

care  being  taken  to  brush  the  powder  well  into  every 
crevice. 

The  Deposition  of  the  Metal. — The  cast  is  now 
connected  to  the  large  copper  wire  which  supports  the 
zinc  plate,  and  is  gently  lowered  into  the  copper  solu- 
tion in  the  outer  jar,  when  the  whole  arrangement  is 
complete.  The  cast  should  remain  in  this  position  until 
the  desired  thickness  of  copper  has  been  deposited. 


THE   DEPOSITION   OF  SILVER. 

In  silver  plating  the  solutions  are  formed  from  silver 
nitrate.  In  preparing  which,  dissolve  i  oz.  of  fine 
silver  in  2  ozs.  of  nitric  acid  and  y2  oz.  of  distilled 
water. 

Method  of  Preparing  Silver  Nitrate. — This  is 
best  accomplished  by  first  placing  the  silver  in  an 
evaporating  dish,  then  adding  the  water,  and  lastly  the 
acid.  A  vigorous  ebullition  then  takes  place,  giving  off 
red  fumes  of  nitrous  gas,  which  are  injurious  and  should 
be  allowed  to  escape  through  the  chimney  or  out  the 
window. 

When  the  action  begins  to  quiet  down  a  little,  the 
dish  should  be  placed  upon  a  warm  sand-bath.  When  the 
fumes  cease  to  appear  the  chemical  action  is  at  an  end. 

It  should  now  be  set  aside  to  cool,  when,  after  a  few 
hours,  crystals  of  silver  nitrate  will  have  deposited, 
from  which  the  remaining  liquid  is  to  be  poured  off. 
Another  method  is  to  evaporate  to  dryness,  by  which  the 
free  acid  is  all  driven  off. 


ARTIFICIAL    DENTURES;    ELECTRO-DEPOSIT.         1 35 

Preparation  of  Silver  Cyanid  Solution. — Dis- 
solve the  prepared  crystals  of  silver  nitrate  in  three  pints 
of  distilled  water,  which  should  be  effected  in  a  glass 
dish,  glazed  earthenware,  or  stoneware  vessel.  Add  to 
this  solution  a  small  quantity  of  common  salt,  a  little 
at  a  time,  until  precipitation  of  silver  chlorid  ceases. 
Now  pour  off  the  clear  solution  and  wash  the  chlorid 
of  silver  several  times  with  distilled  water. 

A  strong  solution  of  potassium  cyanid  (about  y^  a 
pound  to  1  quart  of  water  is  usually  employed)  is  now 
added  to  this  white  precipitate,  a  little  at  a  time,  when 
the  silver  cyanid  will  be  formed.  While  the  solution 
is  being  added  it  should  be  well  stirred  with  a  glass  rod. 
In  making  up  a  quart  of  the  solution,  use  the  i  ounce 
of  fine  silver,  previously  alluded  to,  with  one-quarter 
of  a  pound  of  potassium  cyanide,  and  a  quart  of  dis- 
tilled water. 

Silver  Bronze  for  Plaster  Cast. — In  preparing 
the  silver  bronze  for  the  cast,  place  a  small  quantity  of 
silver  chlorid  in  a  dish  and  add  a  few  drops  of  sulphuric 
acid  and  a  small  piece  of  zinc.  After  all  action  has 
ceased,  the  silver  bronze  thus  formed  is  thoroughly 
washed  and  dried- 

Preparation  of  Plaster  Cast.— Apiece  of  copper 
wire  is  placed  around  the  cast  and  the  ends  twisted  until 
it  is  thoroughly  secured.  The  cast  is  then  immersed  in 
melted  wax,  after  which  *it  is  carefully  and  thoroughly 
coated  with  the  silver  bronze,  which  is  best  applied  with 
the  end  of  the  finger. 

Manner  of  Making  Attachment  to  the   Bat- 


136 


DENTAL   PROSTHESIS    AND    METALLURGY. 


tery. — In  this  work  Nos.  1,  2,  or  3  Bunsen  battery 
may  be  employed.  To  the  wire  coming  from  the  zinc 
of  the  battery,  attach  the  ends  of  the  wire  encircling 
the  cast,  suspending  the  latter  in  the  jar  of  silver  cyanid 
solution.     Then  to  the  wire  coming  from  the  carbon  to 


Fig 


the  silver  solution  attach  a  piece  of  fine  silver,  which  is 
also  suspended  in  the  solution.  The  silver  is  called  the 
anode  and  the  cast  the  cathode.*      These  attachments 

*  The  conductors  immersed  in  the  liquid  to  be  decomposed  are 
termed  positive  and  negative  electrodes.  The  positive  electrode,  or  the 
conductor  by  which  the  current  enters  the  liquid,  is  termed  the  anode, 
and  that  by  which  it  leaves,  or  the  negative,  is  termed  the  cathode. 


ARTIFICIAL   DENTURES;    ELECTRO-DEPOSIT.         1 37 

should  remain  for  about  48  hours,  the  time  required  for 
a  deposit  of  silver  of  sufficient  thickness  for  an  artificial 
denture. 

The  Bunsen  Battery  is  composed  of  an  outside 
glass  or  stone  jar  with  dilute  sulphuric  acid  (sulphuric 
acid  1  part  to  10  of  water).  In  this  is  placed  a 
cylinder  of  stout  sheet  zinc,  well  amalgamated.  A 
porous  cup  or  cell  is  placed  within  the  zinc,  and  in  this 
a  block  of  carbon  is  gently  deposited  (Fig.  53  repre- 
sents this  form  of  battery).  The  cup  is  then  nearly 
filled  with  eight  parts  of  a  saturated  solution  of  bi- 
cromate  of  potash  to  one  part  of  sulphuric  acid,  when 
the  arrangement  is  complete. 


DEPOSITION  OF  GOLD. 

Since  for  the  deposition  of  gold  it  is  necessary  that 
the  metal  be  brought  to  the  state  of  solution,  we  will 
first  consider  the  method  of  preparing  the  salt  com- 
monly known  as  the  chlorid  of  gold ^  but  which,  strictly 
speaking,  is  the  terchlorid,  as  it  contains  three  equiva- 
lents of  chlorin. 

Preparation  of  Gold  Chlorid.  —  The  most  con- 
venient way  to  dissolve  the  gold  is  to  place  the  desired 
quantity  in  an  evaporating  dish  and  add  to  it  a  sufficient 
amount  of  aqua  regia  (2  parts  hydrochloric  acid  and  1 
part  nitric  acid)  to  dissolve  it.  To  dissolve  1  ounce  of 
gold  (troy  weight)  about  4  ounces  of  aqua  regia  is 
required. 

The  chemical  action  which  takes  place  may  be  accel- 
10 


I3S  DENTAL    PROSTHESIS    AND    METALLURGY. 

erated  by  placing  the  dish  upon  a  moderately  heated 
sand-bath.  Heat  should  then  be  gently  applied  to  drive 
off  the  acid,  until  the  mass  assumes  a  dark-red  color 
and  just  ceases  to  flow  about  the  vessel,  at  which 
moment  it  should  be  set  aside  and  allowed  to  cool.* 

The  red  mass,  or  the  gold  chlorid,  is  next  dissolved 
in  distilled  water,  which  will  assume  a  clear,  brownish- 
yellow  color.  If  after  the  chlorid  is  deposited  a  white 
deposit  remains  in  the  bottom  of  the  dish,  it  is  the 
chlorid  of  silver,  resulting  from  a  trace  of  that  metal 
having  been  present  in  the  gold. 

Ammonia  Gold  Cyanid  Solution.  —  To  the 
solution  of  gold  chlorid,  aqua  ammonia  is  added, 
a  little  at  a  time  with  stirring,  until  all  the  gold  is 
thrown  down  in  the  form  of  a  brown  precipitate.  The 
liquid  is  poured  off  and  the  precipitate  or  ammonia 
gold  is  washed  several  times  with  distilled  water.  It  is 
now  dissolved  in  a  strong  solution  of  potassium  cyanid, 
which  is  then  filtered. 

Gold  Bronze. — Take  a  solution  of  gold  chlorid 
and  precipitate  with  a  solution  of  iron  sulphate ;  wash 
thoroughly  and  dry.  This  is  then  used  as  the  gold 
bronze  for  coating  the  cast,  before  attaching  it  to  the 
battery. 

Preparation  of  the  Cast. — The  cast,  as  directed 


*  If  too  much  he*at  is  applied  when  the  solution  has  acquired  the 
dark-red  color,  it  will  quickly  become  reduced  to  the  metallic  state. 
It  would  then  become  necessary,  after  dissolving  out  the  chlorid  with 
distilled  water,  to  test  it  with  aqua  regia,  which  will  redissolve  it. 


ARTIFICIAL  DENTURES;  CONTINUOUS-GUM  PROCESS.     I  39 

for  silver  and  copper  work,  is  encircled  and  well  secured 
by  a  piece  of  copper  wire.  It  is  then  coated  with  the 
gold  bronze,  and  attached  to  the  negative  wire  of  the 
battery  ready  for  action. 

Deposition  of  the  Metal. — The  Bunsen  battery  is 
employed.  A  piece  of  fine  gold  is  soldered  to  a  small 
platinum  wire,  which  is  attached  to  the  copper  wire 
coming  from  the  carbon  of  the  battery,  as  the  anode; 
the  cast  being  attached  to  the  wire  coming  from  the 
zinc,  which  acts  as  the  cathode.  These  are  gently 
lowered  and  left  suspended  in  the  vessel  containing  the 
ammonia  gold  cyanid  solution.  If  this  solution  is 
worked  cold  it  requires  about  five  days  to  deposit  a 
sufficient  thickness  of  gold  for  an  artificial  denture.  If, 
however,  it  is  kept  at  about  1300  F.  the  result  may  be 
accomplished  much  quicker. 

After  the  base  plate  is  thus  secured,  the  teeth  are 
secured  by  means  of  rubber  or  celluloid  attachments. 
See  chapter  upon  the  subject. 


ARTIFICIAL    DENTURES    FORMED    BY 

THE    "  CONTINUOUS-GUM  " 

PROCESS. 

Preliminary  Process. — The  manipulations  con- 
nected with  the  formation  of  the  plaster  model  and 
metallic  swages  are  essentially  the  same  as  in  the  con- 
struction of  ordinary  gold  work.  The  plate,  or  base, 
is  formed  of    pure   platinum    plate,   29    gauge  for  the 


140  DENTAL    PROSTHESIS    AND    METALLURGY. 

upper  and  26  for  lower.  This  being  properly  swaged, 
and  accurately  fitted  to  the  mouth,  the  outer  edge  is 
reinforced  by  soldering  a  small  flattened  wire  (22  gauge) 
around  it.  This  strengthens  the  plate  and  gives  a  good, 
round  finish  to  the  edge,  as  well  as  protects  the  porce- 
lain. Pure  gold  should  always  be  used  for  the  soldering, 
and  just  enough  borax  used  to  direct  the  flow  of  the 
solder. 

The  back  edge  of  the  plate  should  be  doubled,  that 
is,  an  extra  piece  of  platinum  should  be  swaged  and 
soldered  across  it.  This  imparts  increased  strength, 
leaves  some  margin  for  slight  change  in  case  of  necessity 
after  the  plate  is  in  the  mouth,  admits  of  a  neater 
finish,  and  protects  the  edge  of  the  porcelain.  This 
"  doubler  "  should  be  about  three-sixteenths  of  an  inch 
wide,  and  the  inner  edge  should  be  turned  up  slightly, 
before  soldering,  so  as  to  better  receive  the  edge  of  the 
porcelain.  This  turned-up  edge  should  unite  nicely 
with  the  ends  of  the  wire  around  the  tuberosities  so  as 
to  give  a  perfect  finish  and  protect  the  edge  of  the 
porcelain  at  every  point. 

The  bite  is  next  secured  in  the  usual  way,  and  the 
teeth  arranged  and  secured  with  hard  wax,  with  special 
reference  to  the  requirements  of  the  case.  They  are 
then  covered  with  a  thin  coating  of  plaster-of-Paris 
mixed  with  water  to  the  consistency  of  cream.  Allow 
this  to  set  firmly,  then  place  round  on  the  outside  of 
the  previous  covering  a  somewhat  thicker  mixture  of 
plaster  and  asbestos  (one  part  of  the  latter  to  two  of  the 
former),    with   water.     This  investment  is  brought  up 


ARTIFICIAL  DENTURES;  CONTINUOUS-GUM  PROCESS.    141 

over  the  teeth  with  a  spatula,  so  as  to  protect  them  from 
the  flame  in  the  soldering  process. 

Attaching  the  Teeth. — When  the  investment  has 
become  sufficiently  dry  and  hard,  the  wax  is  removed, 
and  boiling  water  dashed  freely  over  the  exposed 
portion  of  the  plate  and  pins  of  the  teeth,  so  as  to 
thoroughly  cleanse  them  for  soldering.  A  rim  or  strip 
of  platinum  is  now  fitted  to  the  plate  and  palatine 
surface  of  the  teeth,  below  the  pins.  This  imparts 
additional  strength  to  the  case. 

The  pins  of  the  teeth,  which  do  not  already  touch 
the  plate  (continuous-gum  teeth  having  unusually  long 
pins  for  this  purpose)  should  be  bent  down  over  this 
rim  and  on  to  the  plate.  When  it  so  happens  that  a  pin 
will  not  touch,  a  small  piece  of  platinum  scrap  is  folded 
beneath,  so  as  to  make  the  connection  complete. 

With  a  small  brush  place  borax  on  the  pins  and  plate 
at  the  points  touching,  and  along  the  edge  between  the 
rim  and  plate.  Small  pieces  of  pure  gold  are  now 
placed  at  all  these  points  of  union.  It  is  all  now  slowly 
introduced  into  a  heated  muffle,  and  brought  gently 
up  to  a  red  heat;  then  withdrawn  from  the  furnace 
and  brought  quickly  under  the  blowpipe  to  flow  the 
gold. 

After  the  case  is  thoroughly  soldered  and  cooled,  the 
investment  is  removed  from  the  teeth,  taking  care  to 
preserve  the  base  portion  for  the  plate  to  sit  upon  dur- 
ing the  subsequent  bakings  of  the  body  and  enamel. 
The  case  should  now,  after  being  thoroughly  cleansed, 
be  tried  in  the  mouth,  and  if  any  changes  have  taken 


142  DENTAL    PROSTHESIS    AND    METALLURGY. 

place  they  should  be  corrected  at  this  time.  Everything 
being  correct,  the  body  can  be  applied. 

Preparing  and  Applying  the  Body. — The  body, 
which  is  supplied  by  dental  dealers  for  this  purpose, 
may  be  mixed  with  water  in  a  small  porcelain  dish  to 
the  consistency  of  cream  ;  this  is  then  applied  in  the 
plastic  state  and  is  distributed  the  desired  thickness  over 
the  surface  of  the  plate  and  around  the  necks  of  the 
teeth,  a  spatula  or  other  small  instrument  being  used  for 
the  purpose.  After  the  body  is  on,  tap  the  plate  occa- 
sionally to  bring  the  moisture  to  the  surface,  which 
should  be  absorbed  writh  a  soft  clean  napkin.  The 
body  should  then  be  carved  with  small  instruments  and 
brush  to  represent  the  gum,  giving  the  desired  fulness, 
contour,  etc.,  and  the  roof  and  rugae  of  the  mouth 
should  be  reproduced,  taking  care  to  keep  the  crowns 
and  necks  of  the  teeth  clean  and  well  defined.  Small, 
clean  cuts  with  a  small  knife  blade  should  then  be  made, 
one  between  each  of  the  teeth.  Commencing  with  the 
space  between  the  molars,  the  cuts  should  be  made 
through  the  body  to  the  rims  and  the  plate,  and  should 
be  both  external  and  internal.  The  object  of  this  is  to 
prevent  movement  of  any  of  the  teeth  from  contraction 
of  the  body  during  baking,  compelling  the  material  to 
shrink  toward  the  teeth,  leaving  smooth  and  irregular 
openings  where  the  incisions  were  made,  into  which 
more  of  the  body  is  packed  and  baked. 

First  Baking. — The  plate  should  now  be  replaced 
upon  the  base  of  investment  material,  upon  which  it 
was  soldered,  and   placed  in   the  upper   muffle  of  the 


Fig.  54- 


144  DENTAL   PROSTHESIS    AND    METALLURGY. 

Fig.  55. 


ARTIFICIAL  DENTURES;  CONTINUOUS-GUM  PROCESS.     1 45 

heating  furnace.  The  Sharp  furnace  is  one  of  the  latest 
and  most  approved  appliances  for  this  work ;  it  is  illus- 
trated both  in  sections  and  complete  in  Figs.  54,  55. 
After  the  case  has  been  placed  in  the  upper  muffle, 
heat  may  be  applied,  slowly  at  first,  but  gradually  in- 
creased as  the  case  is  dried,  until  the  muffle  is  red  hot, 
when  it  is  removed  to  the  lower  muffle  in  the  furnace, 

Fig. 56. 


which,  by  this  time,  will  be  almost  to  a  white  heat. 
Only  a  few  minutes  in  this  muffle  is  necessary  to  bake 
or  biscuit  it.  Continue  to  raise  the  temperature  until 
the  body  presents  shining  crystals,  when  the  heat  may 
be  turned  off  entirely  and  the  case  withdrawn  and 
placed  in  the  upper  muffle.  The  whole  top  in  which  it 
is  encased  can  be  set  off,  thereby  cooling  the  piece  with 
perfect  safety  in  a  much  less  time  than  if  allowed  to  re- 


146 


DENTAL    PROSTHESIS    AND    METALLURGY. 


main  in  the  muffle  in  which  it  was  baked.  As  soon  as 
cold,  replace  and  adjust  to  the  die.  The  appearance  of 
the  case  after  the  first  baking  is  shown  in  Fig.  56. 

Final  Baking. — The  incisions  and  cracks  in  the 
body  should  now  be  packed  carefully  and  perfectly 
with  body ;  this  should  be  jarred  occasionally  and  the 
moisture  well  absorbed   from  the  surface.     Over  this, 

Fig.  57. 


a  thin  and  even  coating  of  enamel  is  applied,  spatula 
and  brush  being  used  for  the  purpose,  care  being 
taken  not  to  allow  any  enamel  to  remain  on  the  teeth, 
and  to  pack  it  very  nicely  around  the  necks.  Now 
carefully  tap  the  plate  with  the  spatula  to  bring  the 
moisture  to  the  surface,  which  absorb  with  the  napkin  ; 
then  dry  and  bake  the  case  again,  bringing  it  to  a  little 


METALLIC    BASE   WITH    RUBBER   ATTACHMENT.       1 47 

higher  temperature,  so  that  more  of  the  shining  crystals 
will  be  seen.  Cool  down  as  before,  and  examine  care- 
fully for  small  cracks ;  if  any  should  be  found,  fill 
them  with  enamel,  and  refire.  The  plate  when  done 
will  present  a  glassy  or  watery  appearance.  The  gas 
must  then  be  turned  off,  and  the  case  allowed  to  cool 
in  the  cooling  muffle.  Fig.  57  illustrates  the  finished 
denture. 


METALLIC    BASE    WITH    RUBBER    OR 
CELLULOID    ATTACHMENT. 

The  method  of  attaching  porcelain  teeth  to  a  metallic 
plate  by  means  of  rubber  or  celluloid  has,  in  full  den- 
tures, many  advantages  over  the  soldering  process.  In 
point  of  cleanliness  and  purity  it  is  much  superior ;  the 
diminished  liability  to  fracture  of  the  teeth  on  account 
of  the  pliable  nature  of  the  attaching  material  used, 
the  facility  with  which  injury  may  be  repaired,  the  prac- 
ticability of  remodeling  the  piece  without  impairment 
of  the  teeth  or  plate,  are  among  the  qualities  which 
commend  this  form  of  denture. 

In  mounting  teeth  by  this  method,  any  of  the  metals 
employed  for  artificial  dentures,  whether  gold,  silver, 
platinum,  aluminum,  cast  metal,  or  that  formed  by  the 
electro-deposit  process,  may  be  used.  When  a  silver 
base  is  used  it  should  be  made  from  refined  silver 
alloyed  with  platinum,  with  the  additional  precaution 
of  interposing  a  layer  of  tin-foil  in  packing  the  case 


148 


DENTAL    PROSTHESIS    AND    METALLURGY. 


between   the  rubber  and   plate ;   this,  however,  is  not 
necessary  when  celluloid  is  used. 

Method  of  Procedure. — After  securing  the 
metallic  base  and  fitting  it  to  the  mouth,  the  "bite" 
should  be  secured  in  the  usual  way  and  the  plaster  cast 
with  the  metal  plate  in  position  should  be  secured  in  an 
articulator.     We    now   proceed    as    for   ordinary   gold 

Fig.  58. 


work,  the  teeth  are  ground  and  jointed  (if  block  or 
gum  teeth  are  used),  and  held  temporarily  in  position 
with  a  little  wax  upon  the  labial  surface.  Next  mark 
with  a  sharp-pointed  instrument  on  the  palatine  surface 
of  the  plate  each  point  where  it  is  desirable  to  solder 
a  pin  or  loop,  which  should  be  as  near  the  base  of  the 
teeth  as  possible,  then  remove  the  teeth  and  wax. 
Now  solder  at  the  points  indicated  either  short  platinum 


METALLIC  BASE  WITH  RUBBER  ATTACHMENT.   1 49 

pins  or  loops  formed  of  small  platinum  wire  or  strips  of 
plate,  soldering,  of  course,  with  a  lower  carat  than  that 
used  in  the  plate ;  bend  or  flatten  the  loops  as  desired  ; 
clean  plate  thoroughly  in  the  acid  bath,  and  polish 
that  portion  to  be  exposed  to  view.  Return  the  plate 
to  the  cast  and  see  that  it  fits  accurately ;  arrange  the 
teeth  according  to  the  articulation ;  wax  up  so  as  to 
entirely  cover  the  pins  or  loops, — in  fact,  the  pins 
should  be  so  placed  that  when  the  palatine  surface  of 
the  rubber  is  properly  shaped  they  will  not  be  exposed 
in  the  least.  The  case  is  now  ready  to  be  flasked,  vul- 
canized, and  finished  up  as  usual.  The  principle  is 
illustrated  in  Fig.  58. 

Another  method  of  increasing  the  attachment 
between  the  metallic  base  and  the  rubber,  is  that  of 
spurring  the  plate  over  the  ridge  with  a  sharp-pointed 
chisel,  as  shown  in  Fig.  59. 

When  aluminum  is  employed  as  the  base,  the  strong- 
est and  altogether  the  best  means  of  increasing  the 
attachment  is  that  of  cutting  or  punching  loops  from 
the  plate  itself.  The  best  instrument  for  this  purpose 
is  that  devised  by  Dr.  J.  H.  Gaskill,  which  is  illustrated 
in  Fig.  60. 

When  a  cast  metal  plate  is  employed,  loops  or  pins 
are  not  needed,  as  sufficient  anchorage  is  secured  by  cut- 
ting out  the  wax  on  the  labial  surface  and  from  between 
the  teeth  (in  fact,  from  every  point  where  it  is  desirable 
to  have  the  rubber)  before  flasking  for  the  casting  pro- 
cess.    After  the  plate  has  been  cast  and  finished,  the 


*5° 


DENTAL    PROSTHESIS    AND    METALLURGY. 


rubber  may  be  packed  and  the  case  re-flasked,  vulcan- 
ized, and  finished  in  the  usual  manner. 


Fig.  59. 


Fig.  60,  a. 


Fig.  60,  b. 


OBTURATORS    AND    ARTIFICIAL   VELUM.  151 

OBTURATORS  AND  ARTIFICIAL 
VELUM. 

Palatine  defects  are  divided  into  two  classes,  acci- 
dental and  congenital.  The  first,  includes  all  loss  of 
substance  in  either  hard  or  soft  palate  by  disease  or 
accident  after  birth.  The  second  class  includes  all  mal- 
formations of  the  palatine  organs,  from  the  simple  divi- 
sion of  the  uvula  to  an  opening  through  the  entire  pala- 
tine and  maxillary  bones,  which  may  exist  at  birth. 

Obturator. — The  term  obturator,  properly  speaking, 
is  employed  for  all  appliances  intended  to  stop  a  pas- 
sage in  the  hard  or  soft  palate  which  may  have  a  com- 
plete and  well-defined  boundary. 

Artificial  velum  is  the  term  for  all  appliances  made 
to  supply  the  loss  of  the  posterior  soft  palate. 

The  different  forms  of  appliances  in  general 
use  are  known  as  Kingsley's,  Suerson's,  and  Baker's. 

Kingsley's  Methods. — A  simple  obturator  for 
hard  palate,  without  teeth  or  clasps,  is  represented  in 
Fig.  61,  and  is  intended  for  a  perforation  of  the  hard 
palate,  being  sustained  in  situ  by  impinging  slightly 
upon  the  natural  teeth  with  which  it  comes  in  contact. 

As  Dr.  Kingsley  says  of  this,*  accuracy  of  adaptation 
and  delicacy  in  form  are  all  that  is  essential  in  such 
cases,  and  the  restoration  of  speech  will  follow. 

Obturator  for  Soft  Palate. — The  construction  of 

*  See  chapter  on  Obturators,  Richardson's  Mechanical  Dentistry, 
6th  Edition,  where  the  subject  is  treated  in  detail. 


/ 


!52 


DENTAL    PROSTHESIS    AND    METALLURGY. 


an  obturator  for  the  soft  palate  is  much  more  compli- 
cated. As  Dr.  Kingsley  says,  the  necessity  for  a  varia- 
tion in  the  plan  will  be  found  in  the  anatomical  fact 
of  the  constant  muscular  action  of  the  soft  palate, 
which  would  not  permit,  without  irritation,  the  pres- 
ence of  an  immovable  fixture. 

This  is  contrived  with  a  joint  that  will  permit  the 
part  attached  to  the  teeth  to  remain  stationary,  while 
the  obturator  proper  is  carried  up  or  down  as  moved 


Fig.  6i. 


Fig.  62. 


by  the  muscles  (See  Fig.  62).  The  joint,  a,  should 
occupy  the  position  of  the  junction  of  the  hard  and 
soft  palates.  The  joint  and  principal  part  of  the  appli- 
ance is  made  of  gold,  the  obturator  of  vulcanite.  The 
projection,  b,  lies  like  a  flange  upon  the  superior  surface 
of  the  palate  and  sustains  it ;  otherwise  the  mobility  of 
the  joint  would  allow  it  to  drop  out  of  the  opening. 
This  flange  is  better  seen  in  the  side  view  marked  c.  It 
is  readily  placed  in  position  by  entering  the  obturator 
first,  and  then  carrying  the  clasps  to  the  teeth. 


OBTURATORS    AND    ARTIFICIAL   VELUM. 


J53 


Artificial  Palates. — The  following  case  (Fig.  63) 
presents  some  unusual  difficulties  in  not  having  any 
teeth  to  aid  in  supporting  the  appliance,  making  it 
necessary  to  adopt  a  plate  which  should  not  only  sustain 
the  teeth  for  mastication,  but  bear  the  additional 
responsibility  of  supporting  the  artificial  plate. 

Fig.  63. 


Fig.  64  illustrates  the  appliance  as  prepared  for  the 
mouth.  The  plate  was  made  of  gold  and  formed  as 
is  usual,  except  at  the  median  line  on  the  posterior  bor- 
der (marked  c),  where  a  groove  was  located  to  receive 
the  attachment  for  the  artificial  palate.  The  wings 
marked  a  and  b  are  made  of  soft  rubber ;  the  frame  to 
support  them  is  made  of  gold,  with  a  joint  to  provide 
11 


i54 


DENTAL    PROSTHESIS   AND    METALLURGY. 


for  the  perpendicular  motion  of  the  natural  palate,  as 
in  the  case  of  the  obturator  represented  in  Fig.  62. 


Fig.  64. 


Fig.  65  represents  the  artificial  palate  separated  into 


Fig.  65. 


its   several  parts.     Letter  c   shows  the  tongue,  which 
enters  the  groove  in  the  plate  and  connects  them. 


OBTURATORS    AND    ARTIFICIAL    VELUM. 


155 


Artificial   Palates   for   Congenital   Fissure. — 

To  further  illustrate  Dr.  Kingsley's  methods,  the  fol- 
lowing case  (the  details  of  which  are  given  in  "  Rich- 
ardson's Mechanical  Dentistry")  is  presented. 

Fig.  66  represents  a  model  of  a  fissured  palate,  com- 
plicated with  hare-lip  on  the  left  side  of  the  mesial  line. 

Fig.  66. 


There  is  a  division,  also,  of  the  maxilla  and  the  alveolar 
process,  the  sides  being  covered  with  mucous  membrane, 
which  come  in  contact  with  each  other  but  are  not 
united.  The  left  lateral  incisor  and  left  canine  tooth 
are  not  developed. 

Fig.  67  represents  the  artificial  velum,  as  viewed  from 


156 


DENTAL   PROSTHESIS   AND    METALLURGY. 


its  superior  surface,  together  with  the  attachment  and 
two  artificial  teeth  to  fill  the  vacancy. 

The  lettered  portion  of  this  appliance  is  made  of  soft 
vulcanized  rubber;  its  attachment  to  the  teeth  of  hard 
vulcanized  rubber,  to  which  the  velum  is  connected  by 
a  stout  gold  pin  firmly  embedded  at  one  end  in  the  hard 
rubber  plate.  The  other  end  has  a  head,  marked  c, 
which,  being  considerably  larger  than  the  pin,  and  also 
the  corresponding  hole  in  the  velum,  it  is  forced  through, 


Fig.  67. 


the  electricity  of  the  velum  permitting,  and  the    two 
are  securely  connected. 

Dr.  Suersen's  Methods. — The  principles  of  the 
appliance  introduced  by  Dr.  Wilhelm  Suersen,  of  Ber- 
lin, has  seemed  to  many  to  be  the  best  for  obtaining 
correct  articulation.  An  ordinary  plate  is  constructed, 
suitably  attached  to  the  existing  teeth  and  covering  any 
fissure  that  may  exist  in  the  hard  palate.  From  the 
posterior  border  of  this  plate,  in  the  center  of  the  fissure, 
a  hard  and  stationary  bulb,  which  may  be  either  hollow 
or  solid  and  which  will   form   the  artificial  palate,  or 


OBTURATORS    AND    ARTIFICIAL   VELUM. 


157 


velum,  is  attached.  This  method  is  illustrated  in  the 
accompanying  illustrations,  Figs.  68,  69,  and  70. 

As  will  be  seen,  Fig.  68  represents  the  mouth  without 
the  apparatus ;  Fig.  69  shows  it  in  position  ;  Fig.  70 
gives  a  view  of  the  appliance  itself. 

The  simplest  manner  of  constructing  the  bulb  is  to 

Fig.  68. 


leave  a  small  projection  of  rubber  in  the  center  of  the 
posterior  border  of  the  plate  ;  then,  after  vulcanizing  and 
fitting  the  plate  accurately  to  the  mouth,  build  up  upon 
this  projection  a  bulb  composed  of  modeling  compo- 
sition ;  construct  this,  as  near  as  possible,  to  fit  the 
fissure  in  the  soft  palate,  carry  plate  and  bulb  to  position 
in  the  mouth ;  note  any  changes  that  need  to  be  made 
in  the  shape  of  the  latter;  remove  and  trim  away  until 


I58  DENTAL    PROSTHESIS    AND    METALLURGY. 


Fig.  69. 


Fig.  70. 


OBTURATORS    AND    ARTIFICIAL    VELUM. 


'59 


the  desired  shape  and  adaptation  is  secured.     The  case 
is  then  ready  to  be  flasked,  packed,  and  vulcanized. 

Dr.  Baker's  Methods. — The  appliance  known  as 
the  Baker  Velum  is  illustrated  in  Fig.  71.  It  consists  of 
a  gold  or  hard  rubber  plate  covering  the  roof  of  the 
mouth  down  to  the  junction  of  the  hard  and  soft  palates. 
From  this  point  the  movable  portion,  F,  extends  back 

Fig.  71. 


and  downward,  restoring  symmetry  of  the  palatal  sur- 
face by  bridging  across  and  lying  upon  the  muscles  of 
each  side.  The  spring,  C  E,  controls  the  upward  move- 
ment of  the  bulb,  F,  the  distal  surface  of  which,  G,  is 
quite  broad,  and  so  constructed  as  to  articulate  with  the 
pharyngeal  wall,  while  the  constrictor  muscle  contracts 
and  closes  around  it  on  a  semicircle.  This  is  the 
Suersen  principle,  and  the  main  ideas  are  taken  from 
that  appliance. 


l6o  DENTAL   PROSTHESIS    AND    METALLURGY. 

INTERDENTAL   SPLINTS. 

Interdental  splints  are  appliances  used  in  the 
treatment  of  fractured  jaws.  They  are  usually  con- 
structed of  vulcanite  rubber,  and  are  divided  into  double 
and  single  splints.  The  double  splint,  being  the  one 
usually  employed,  will  be  described  in  this  place. 

Taking  the  Impression. — The  impression  of  both 
jaws  should  be  taken,  either  in  wax  or  modeling  com- 
pound, using  as  small  a  quantity  as  will  insure  a  good 
impression  of  the  teeth  and  gums. 

As  it  is  impossible  to  keep  the  fragments  of  a  frac- 
tured inferior  jaw  in  perfect  apposition  while  taking  an 
impression,  no  attempt  should  be  made  to  entirely  reduce 
the  fracture  at  this  time.  The  sections,  however,  should 
be  brought  as  nearly  to  position  as  possible  without 
causing  much  pain  to  the  patient. 

An  assistant  should  stand  behind  the  patient  and  sup- 
port the  broken  jaw,  keeping  it  steady  while  the  impres- 
sion is  being  taken.  This  being  more  important  when 
the  fracture  is  double. 

The  impression  material  being  ready,  it  should  be 
introduced  into  the  mouth  and  carefully  brought  to 
position.  Much  care  should  be  exercised  to  prevent  the 
pieces  of  bone  and  loosened  teeth  from  moving  when 
this  material  is  being  molded  about  their  necks. 

Preparing  the  Models. — After  the  impression  has 
been  secured,  mix  plaster  and  pour  cast  in  the  usual 
manner.  Fig.  72  represents  a  cast  showing  a  double 
fracture. 


INTERDENTAL    SPLINTS. 


161 


The  casts  or  models  of  both  jaws  being  obtained,  they 
should  be  carefully  articulated.  This  is  done  by  cutting 
(with  a  small  saw)  the  lower  cast  at  the  point  or  points 


Fig.   72 


Fig.  73. 


of  fracture,  and  rearranging  the  sections  thus  made  so 
as  to  bring  the  teeth  of  the  two  models  into  correct 
articulation.     This  is  represented  in  Fig.  73. 


1 62  DENTAL    PROSTHESIS    AND    METALLURGY. 

The  pieces  should  then  be  secured  in  this  position 
with  plaster  and  the  two  models  placed  in  an  articu- 
lator. 

Forming  the  Splint  in  Wax. — Any  interdental 
dovetail  spaces  should  be  filled  with  soft  plaster,  so  that 
the  splint  when  finished  can  be  readily  adjusted  and 
removed. 

The  articulator  should  now  be  arranged  (by  the  set 
screw  in  the  back)  so  as  to  open  the  bite  about  half  an 
inch.  Carefully  cover  teeth  and  gums  of  both  casts 
with  No.  60  tin-foil.  Over  this  covering  of  tin-foil 
build  up  the  splint  in  wax.  This  is  best  done  as  directed 
by  the  late  Dr.  Alonzo  Beal.*  First,  place  two  layers  of 
thin  base-plate  wax  over  the  teeth  of  both  models, 
allowing  it  to  extend  just  beyond  the  necks  of  the  teeth 
upon  the  gums,  but  not  quite  to  the  edge  of  the  tin-foil. 
Then  make  a  strip  of  wax  about  three-sixteenths  of  an 
inch  thick  and  wide  enough  to  fit  between  the  pieces  of 
wax  on  the  models,  and  long  enough  to  extend  as  far 
back  as  they  do,  joining  the  three  pieces  together  with 
melted  wax.  Pass  a  hot  spatula  all  around  the  edge  of 
the  wax,  where  it  joins  the  tin-foil,  to  make  a  perfect 
joint.  The  object  of  the  tin-foil  is  to  make  the  rubber 
smooth,  and  to  have  the  splint,  when  finished,  a  trifle 
larger  than  the  natural  teeth,  so  that  it  will  pass  in 
position  without  binding  at  any  point. 

Flasking. — The  wax  splint  and  tin-foil  covering, 
now   being  one  piece,  should    be  removed    from    the 


*  See  American  System  of  Dentistry,  Vol.  II. 


INTERDENTAL    SPLINTS. 


163 


models  and  the  models  carefully  taken  from  the  articu- 
lator, trimming  their  bases  and  sides  if  necessary,  so 
that  when  the  splint  is  in  position  on  them  the  whole 
will  fit  in  the  vulcanizing  flask.  The  lower  model  with 
the  splint  upon  it  should  be  flasked  first,  and  the  invest- 
ment allowed  to  extend  half-way  up  the  splint.  Trim, 
varnish,  and  oil.     Place  the  upper  model  in  position  in 


Fig.  74. 


the  splint  and  finish  flasking.  By  allowing  the  tin-foil 
to  extend  beyond  the  wax  (as  at  T,  Fig.  74)  the  invest- 
ment holds  it  in  position  when  the  wax  is  removed. 
Fig.  74  gives  a  sectional  view  of  the  flask  with  the 
splint  invested.  F  represents  the  flask;  M,  the  models; 
P,  plaster  investment;  T,  tin-foil  coverings  of  the  teeth 
extending  beyond  the  wax  splint ;  W,  wax  model  of 
splint.     Before  opening  the  flask,  place  it  in  hot  water 


164 


DENTAL    PROSTHESIS   AND    METALLURGY. 


to  soften  the  wax.  Separate  the  sections  carefully. 
Wash  the  wax  out  by  pouring  boiling  water  upon  it, 
instruments  not  being  used,  as  they  are  liable  to  injure 
the  tin-foil. 

Packing  and  Vulcanizing. — Liberal  outlets  for 
the  rubber  should  be  made  in  both  sections.  Cut  the 
rubber  into  thin  strips  and  soften  over  boiling  water. 
It  is  also  advisable  to  cut  up  a  piece  of  previously  vul- 

Fig.  75. 


canized  rubber,  small  pieces  of  which  may  be  packed  in 
between  the  other  rubber  at  the  thickest  points,  making 
it  less  liable  to  become  porous  in  vulcanizing.  Pack  each 
section  carefully  and  thoroughly  a  little  more  than  full. 
Place  the  sections  together,  boil,  and  close  them  in  the 
usual  way.  In  vulcanizing,  allow  the  mercury  one  hour 
to  rise  to  320  F.  When  this  point  is  reached  the  tem- 
perature should  be  kept  uniform  for  one  hour  or  more. 
Finishing. — When  the  flask  is  taken  from  the  vul- 


INTERDENTAL    SPLINTS.  1 65 

canizer  and  has  become  cold,  carefully  remove  the 
plaster  and  tin-foil  from  the  rubber.  In  trimming,  the 
rubber  should  be  cut  away  nearly  to  the  necks  of  the 
teeth  and  the  edges  all  nicely  rounded.  The  opening 
made  in  the  splint  for  feeding  purposes  should  be  in 
front  if  possible,  and  large  enough  to  allow  for  the 
free  passage  of  a  feeding-tube,  and  should  have  the 
edges  well  rounded.  The  entire  piece  should  be  nicely 
polished,  and  no  ragged  or  sharp  edges  left.  Fig.  75 
represents  the  completed  splint.  It  is  often  advisable  to 
make  openings  through  the  top  or  side  of  the  splint 
against  each  tooth  adjoining  the  fracture,  so  that  it  can 
be  determined  when  the  fractures  are  in  place.  This 
plan  is  represented  in  Fig.  76. 

Securing  Splint  in  the  Mouth. — The  splint  is 
now  ready  to  be  adjusted  in  the  mouth,  and  if  the  fore- 
going instructions  have  been  closely  followed  the  teeth 
of  the  superior  jaw  will  readily  slip  into  place.  After 
so  placing  it,  carefully  manipulate  the  lower  jaw,  reduc- 
ing the  fracture  and  bringing  the  teeth  to  position  in  the 
splint.  The  jaw  should  then  be  firmly  secured  by 
external  bandages. 

The  Kingsley  Splint. — A  splint  devised  by  Dr. 
Norman  W.  Kingsley  consists  of  a  vulcanite  covering  to 
the  lower  teeth,  having  two  steel  wires  attached  extend- 
ing out  of  the  corners  of  the  mouth  and  then  backward 
along  the  cheek  on  a  line  with  the  teeth.  It  is  held  in 
position  by  having  the  wires  bound  to  a  sub-metal  splint 
of  padded  wood.  The  upper  teeth  must  articulate  with 
the  upper  surface  of  the  rubber,  so  that  the  patient  can 


i66 


DENTAL    PROSTHESIS   AND    METALLURGY. 


use  it  for  mastication.  Take  upper  and  lower  impres- 
sions; pour  models  and  articulate  them,  as  before 
described,  and  place  them  in  an  articulator.  Upon  the 
lower  model  carefully  press  a  piece  of  wax  about  one 
line  in  thickness  over  the  teeth,  allowing  it  to  encroach 
a  little  upon  the  gums.     Close  the  articulator  to  make 

Fig.  76. 


the  imprints  of  the  upper  teeth  in  the  wax.  The  best 
method  to  make  the  arms  is  to  use  a  couple  of  old  den- 
tal excavators.  Flatten  the  ends  which  are  to  be 
embedded,  and  curve  them  carefully,  so  that  they  will 
pass  out  of  the  mouth  and  extend  backward  without 
pressing  hard  on  the  corners  of  the  mouth,  and  termi- 


CORRECTION    OF    DENTAL    IRREGULARITIES. 


167 


nate  near  the  angle  of  the  jaw.  The  flattened  ends 
should  be  made  quite  broad,  and  be  thoroughly  embed- 
ded in  the  splint,  as  much  strain  comes  upon  them. 
Fig.  77  represents  this  form  of  splint. 

Fig.  77. 


APPLIANCES   FOR  THE  CORRECTION 
OF  DENTAL  IRREGULARITIES. 

Orthodontia  is  that  branch  of  dental  science  which 
pertains  to  the  correction  of  irregularity  in  the  position 
of  the  human  teeth. 

The  growth  of  this  branch  of  dental  practice  re- 
quires special  study,  investigation,  and  training  in 
order  to  successfully  practice  it  along  the  advanced 
lines;  every  student  should  make  himself  thoroughly 
familiar  with  the  subject  before  attempting  its  practice. 


1 68  DENTAL   PROSTHESIS    AND    METALLURGY. 

It  will  meet  our  purpose  here,  however,  to  simply 
introduce  a  few  of  the  most  important  methods  involved, 
with  the  manner  of  constructing  the  appliances,  as  a 
stepping  stone  for  students  to  the  study  of  the  more 
exhaustive  works  of  Farrer,  Kingsley,  Guilford,  and 
Talbot. 

Mechanical  Forces. — The  operator  in  this  field 
of  practice  has  an  opportunity  to  utilize  his  knowledge 
of  physics  and  the  laws  of  mechanics.  As  a  very  able 
writer,  Dr.  Eugene  Talbot,  says :  These  laws  are 
founded  upon  the  action  of  simple  elements  which  are 
interposed  between  the  moving  power  and  the  resistance, 
for  the  purpose  of  changing  the  direction  of  the  force. 
These  are  called  mechanical  powers,  and  are  divided 
into  two  primary  elements,  the  lever  and  the  inclined 
plane.  The  principle  of  the  lever  is  the  basis  of  the 
pulley,  the  wheel,  and  axle.  That  of  the  inclined  plane 
is  the  basis  of  the  wedge  and  screw. 

Elasticity,  as  shown  in  India-rubber  and  the  spring 
of  metals,  although  not  classified  with  the  primary  forces 
in  mechanics,  plays  an  important  part  in  the  applica- 
tion of  force  in  regulating  teeth.  When  these  laws  and 
their  applications  are  firmly  fixed  in  the  mind  of  the 
operator,  he  can  readily  take  advantage  of  the  one 
which  should  properly  be  applied,  or,  when  necessary 
to  apply  more  than  one,  can  combine  them  in  such  a 
manner  as  will  best  accomplish  the  desired  result. 

Materials  Employed. — The  materials  employed 
in  regulating  are  platinum,  platinized  gold,  iridio-plati- 
num,  gold,  German  silver,  steel,  vulcanized  rubber,  soft 


CORRECTION    OF    DENTAL    IRREGULARITIES.  1 69 

rubber  bands,  compressed  wood,  sea-tangle,  and  silk, 
linen,  or  cotton  ligatures. 

The  most  frequent  forms  of  irregularity  are 
protrusion  of  the  cuspid  teeth,  misplaced  bicuspids, 
contraction  of  arch,  protrusion  of  the  upper  jaw,  pro- 
trusion of  the  lower  jaw,  torsion,  and  lack  of  anterior 
occlusion. 

Protrusion  of  the  Cuspid  Teeth. — In  correcting 
this  form  of  irregularity,  which  is  possibly  the  most 
frequent  met  with,  we  have  to  decide  from  other  exist- 
ing circumstances  whether  the  enlargement  of  the  arch 
is  indicated  or  the  extraction  of  a  tooth  posterior  to  the 
cuspid.  If  the  upper  arch  is  large  enough,  the  simple 
extraction  of  the  first  or  second  bicuspid  teeth  will 
allow  the  cuspid  teeth  in  a  young  person  to  move  down 
and  back  into  place  unaided.  Where  it  is  desired  to 
hurry  the  operation,  or  where  the  bone  is  too  hard  to 
permit  nature  to  move  the  tooth  sufficiently,  appliances 
as  are  illustrated  in  Figs.  78  and  79  are  usually 
employed.  Fig.  78  shows  Prof.  Guilford's  method, 
which  is  one  of  the  simplest  and  most  effective. 

A  platinum  band,  with  short  gold  wires  soldered  to 
the  buccal  and  lingual  surfaces,  is  cemented  to  the  tooth 
to  be  moved,  while  a  similar  one  is  attached  to  a  molar 
or  other  anchor  tooth.  The  wires  on  the  anterior  band 
are  bent  forward,  and  those  on  the  posterior  one  are 
curved  backward.  Two  rubber  rings,  caught  over  the 
gold  hooks,  connect  the  two  bands  and  yield  the  tractile 
power  required.  These  rubber  rings  can  be  removed 
and  replaced  for  cleansing  the  teeth,  or  can  be  renewed 

13 


170 


DENTAL    PROSTHESIS    AND    METALLURGY. 


at  will  by  the  patient.  Two  rings  can  be  attached  to 
each  pair  of  hooks,  if  greater  power  be  required,  or  the 
same  object  can  be  attained  by  cutting  wider  rings 
from  thicker  tubing. 

Fig.  79  illustrates  another  simple  appliance  for  draw- 
ing a  cuspid  backward  and  inward.  This  was  devised 
by  Prof.  E.  H.  Angle,  and  is  a  part  of  what  is  known 

Fig.   78. 


as  the  "Angle  system  of  regulating,"  which  is  one 
of  the  best,  most  complete,  and  simplest  systems  ex- 
tant. 

The  first  molar  is  encircled  by  a  metallic  band,  to 
which  is  soldered  a  piece  of  tubing  to  accommodate  the 
traction  bar  or  screw.  A  band  is  also  fitted  to  the 
cuspid;  to  this  a  short  tube  is  soldered  on  the  palato- 
distal  portion,  into  which  the  bent  end  of  the  traction 
screw  bar   is  engaged.       The    nut,  which   is   operated 


CORRECTION    OF    DENTAL    IRREGULARITIES.  171 

against  the  distal  end  of  the  tube,  will  readily  move  the 
tooth  into  position. 

Correction  where  Cuspid  Tooth  is  Inside  the 
Arch. — The  power  usually  necessary  to  move  an  in- 
lying cuspid  is  very  great.  The  jack-screw  is  therefore 
one  of  the  best  forms  of  appliance  ;  this,  however,  may 
sometimes  be  aided  by  what  is  known  as  the  inclined 

Fig.  79. 


plane.  Dr.  Angle's  method  is  shown  in  Fig.  80.  The 
base  of  the  tube  containing  the  screw-bar,  or  jack-screw, 
is  soldered  to  a  band  encircling  the  opposite  cuspid  and 
reinforced  by  a  spur  resting  against  the  first  bicuspid 
(see  illustration),  and  also  by  the  large  traction  screw, 
which  is  hooked  into  a  pipe  soldered  to  the  labial  sur- 
face of  the  band  and  passing  in  front  of  the  incisors 
through  a  tube  soldered  to  a  band  on  the  labial  surface 


172 


DENTAL    PROSTHESIS   AND    METALLURGY. 


of  the  lateral  incisor,  against  which  the  nut  works.  In 
this  case,  the  left  central  and  lateral  were  moved  forward 
in  the  line  of  the  arch,  thereby  closing  the  space  between 
the  centrals,  and,  at  the  same  time,  providing  space  for 
the  out-moving  cuspid.  The  large  screw  was  beaten 
flat  and  polished  before  insertion. 

The  Inclined  Plane. — One  of  the  earliest  methods 
employed  in  correcting  or  aiding  to  do  so,  where  the 

Fig.  80. 


Fig.  81. 


superior  cuspid  or  incisor  teeth  were  interlocked,  was 
what  is  known  as  the  inclined  plane.  This  is  formed  of 
metal,  by  first  striking  up  a  saddle  to  cover  two  or  more 
of  the  lower  incisors.  To  this,  at  the  desired  point,  is 
soldered  an  inclined  piece  of  heavy  metal  so  directed 
that  when  the  appliance  is  cemented  in  position,  the 
inlocked  tooth  will  strike  upon  it  in  mastication  and  be 
forced  outward  into  line.  Fig.  81  shows  a  form  of  this 
appliance. 


CORRECTION    OF    DENTAL    IRREGULARITIES.  1 73 

Misplaced  Bicuspids. — A  simple  method  of  mov- 
ing a  bicuspid  out  into  line  is  the  small  jack-screw  of 
the  Angle  system. 

Another  very  ingenious  method  is  the  Jackson  crib 
and  spring  appliance.*  Fig.  82  shows  such  an  appli- 
ance in  position.     A  base  wire  is  shaped  to  the  lingual 


Fig.  82. 


Fig.  83. 


side  of  the  anterior  teeth  and  anchored  to  the  bicuspids 
by  means  of  a  single  "  crib  "  appliance.  To  each  of 
these  latter  is  attached  a  hook  or  eyelet  to  sustain  a 
straight  bar  of  spring  wire  that  is  sprung  over  the 
anterior  teeth. 

Dr.  Jackson  gives  another  very  simple  fixture  for  the 


*  Devised  by  Dr.  V.  H.  Jackson,  of  New  York,  who  has  kindly 
placed  much  of  his  material  upon  the  subject  at  our  disposal. 


174 


DENTAL    PROSTHESIS    AND    METALLURGY. 


purpose  of  moving  a  single  bicuspid  either  inward  or 
outward.     It  is  shown  in  Fig.  83. 

A  spring  wire  is  bent  in  the  form  of  a  crib  surround- 
ing the  misplaced  tooth  and  an  adjoining  one  on  each 
side,  passing  well  up  toward  the  gum  on  the  labial  and 
lingual  sides,  with  the  ends  of  the  spring  wire  terminat- 
ing and  overlapping  upon  the  tooth  to  be  moved.    The 

Fig.  84. 


elasticity  of  the  spring  will  exert  enough  force  to  move 
the  tooth. 

Contraction  of  the  Arch. — The  enlargement  of 
the  arch  by  lateral  expansion  may  be  accomplished  by 
a  number  of  methods.  Older  practitioners  usually  make 
use  of  the  Coffin  split  plate,  but  it  is  the  author's  opin- 
ion that  heavy,  cumbersome  appliances  should  be  dis- 
carded as  far  as  possible.  Among  the  neatest  and  most 
effective  for   this   purpose   are    those    devised    by    Dr. 


CORRECTION    OF    DENTAL    IRREGULARITIES.  1 75 

Eugene  Talbot  and  Prof.  Angle.     Dr.  Talbot's  method 
is  as  follows  :  — 

A  vulcanite  plate  is  made  to  fit  the  teeth  and  alveo- 
lar process,  and  cut  away  so  that  the  anterior  parts  ex- 
tend far  enough  forward  to  enclose  the  teeth  to  be 
moved.  See  Fig.  84.  A  piece  of  piano  wire  is  bent 
into  either  of  the  forms  shown  in  Fig.  85,  wherein  a  is 


the  coil  and  fixed  point ;  b  b,  movable  arms  extending 
from  #,  and  c  c,  movable  arms  extending  from  b  b. 
Grooves  are  cut  into  the  anterior  and  posterior  parts  of 
the  plate  to  correspond  with  and  receive  the  points  b  b 
and  c  c.  Holes  are  drilled  at  these  points,  and  the  wires 
tied  to  the  rubber  plates.  In  order  that  the  anterior 
teeth  may  be  moved  with  the  greatest  force,  the  arms 
are  so  adjusted  that  the  greatest  pressure  is  exerted  on 
the   anterior   parts   of  the    plate.       This   appliance    is 


176 


DENTAL    PROSTHESIS    AND    METALLURGY. 


readily  removed  for  cleansing  and  returned  to  place  by 
the  patient. 

Dr.  Angle's  method  utilizes  the  principle  of  the 
Coffin  spring  without  the  objectionable  features  of  the 
rubber  plate. 

It  can  be  used  either  in  the  upper  or  lower  arch,  and 

Fig.  86. 


where  no  greater  power  than  the  spring  affords  is 
needed,  will  prove  very  efficient.  As  seen  in  the  cut 
(Fig.  86),  a  rubber  ligature  may  be  attached  to  the 
center  of  the  spring  and  be  connected  with  any  cross- 
bar appliance  upon  the  incisors  for  drawing  them  in- 
ward when  such  additional  movement  is  desired. 

Protrusion    of   the    Upper  Jaw. — One   of    the 
simplest  and    most  efficient    methods  of   reduction  in 


CORRECTION    OF    DENTAL    IRREGULARITIES.  177 

superior  protrusion    is    that    given    by  Dr.   Angle.     It 
consists  of  anchor-bands    (D,  Fig.   87)    for  the   molar 

Fig.   87. 


teeth,  with  long  tubes  soldered  to  their  buccal  surfaces 
to  receive  the  wire  bow-spring,  which  rests  in  front  in 
notched  projections  upon  bands  cemented  to  the  central 
incisors.     At  the  center  of  the  bow-spring  is  soldered 


Fig. 


a  short  tube,  having  upon  its  labial  surface  a  rounded 
projection  to  receive  the  standard  (cupped  at  its  free 
end)  of  the  long  traction  bar,   Fig.  S8.     In    use,  the 


i78 


DENTAL    PROSTHESIS    AND    METALLURGY. 


clamp-bands  (D)  are  attached  to  the  anchor-teeth,  and 
the  plain  bands  cemented  to  the  central  incisors.  The 
bow-spring  is  now  placed  in  position. 

Occipital  resistance  is  obtained  by  means  of  a  netted 
cap,  fastened   to  a  circle  of  wire  fitted  to  the  head,  to 


Fig.  89. 


Night  Appliance. 

which  are  attached  rubber  bands.  When  the  cupped 
standard  of  the  traction  bar  has  been  placed  over  the 
central  spur  of  the  bow-spring,  the  rubber  bands  of  the 
cap  are  drawn  forward  and  looped  over  the  curved  ends 
of  the   traction  bar,  as  shown  in   Fig.  89.     This  cap, 


CORRECTION    OF    DENTAL    IRREGULARITIES. 


179 


traction  bar,  and  rubber  bands  are  worn  only  at  night, 
on  account  of  their  conspicuousness. 

During  the  day,  rubber  rings  (B,  Fig.  87)  are  caught 
over  the  tubes  on  the  molar  bands  and  secured  by  liga- 
tures to  projections  on  the  bow-spring  in  the  region  of 
the  cuspid  teeth. 

Fig.  90. 


Day  Appliance. 


The  appliance  in  position,  as  worn  during  the  day,  is 
illustrated  by  Fig.  90.  After  reduction  of  anterior 
protrusion  we  are  met  with  the  difficulty  of  retaining 
the  results  gained.  Although  the  posterior  teeth  in 
many  cases  will  not  furnish  the  resistance  necessary  for 
drawing  the  anterior  teeth  inward,  they  will  usually 
answer  perfectly  for  retaining  them  afterward.     Attach- 


I  So  DENTAL    PROSTHESIS    AND    METALLURGY. 

ment  can  be  made  to  them  either  by  means  of  a  rubber 
plate  covering  the  roof  of  the  mouth  and  extending 
around  their  distal  surfaces  in  the  form  of  a  clasp,  or  by 
means  of  metal  bands  cemented  to  them.  In  the 
former  case  a  small  round  or  half-round  gold  wire  may 
be  made  to  pass  around  the  arch,  touching  the  regulated 
teeth  on  their  labial  surfaces,  and  be  attached  at  each 
end  to  the  rubber  plate  at  convenient  points,  as  where 
teeth  have  been  extracted.  In  the  latter  case  a  similar 
retaining  wire  may  be  soldered  to  the  molar  bands,  or 
the  bands  may  have  tubes  soldered  to  their  buccal  sur- 
faces and  the  wire,  threaded  at  the  extremities,  passed 
through  these  and  retained  by  means  of  nuts  operating 
upon  them.  In  either  case  the  retaining  wire  should 
have  short  gold  clips  attached  to  it  in  front  to  engage 
with  the  cutting  edges  of  at  least  two  of  the  incisor 
teeth. 

When  it  is  desired  to  avoid  having  a  retaining  wire 
pass  entirely  around  the  front  of  the  arch,  a  rubber  re- 
taining plate  may  be  made  with  a  gold  T  passing  be- 
tween the  centrals  and  long  enough  to  rest  upon  all  four 
of  the  incisors.  Holding  these  teeth  firmly  in  place  will 
also  keep  the  cuspids  in  line  through  lateral  pressure. 

Protrusion  of  the  Lower  Jaw. — When  this  de- 
formity is  slight,  it  may  usually  be  corrected  by  drawing 
the  lower  incisors  in  and  the  upper  ones  outward. 
Where  the  case  is  a  pronounced  one,  there  is  no  remedy 
except  the  retraction  of  the  entire  lower  jaw.  In  many 
cases,  however,  the  two  measures  can  be  combined  to 
advantage. 


CORRECTION    OF    DENTAL    IRREGULARITIES.  161 

Method  of  Retraction. — It  was  for  many  years 
supposed  that  the  retraction  of  the  inferior  maxillary 
was  brought  about  entirely  by  a  change  effected  at  the 
angle  of  the  jaw ;  but  some  years  ago  it  was  noticed  by 
Prof.  C.  N.  Peirce,  that  where  sufficient  pressure  was 
brought  to  bear,  a  change  was  brought  about  in  the 
temporo-maxillary  articulation.  That  is,  if  pressure  was 
continued  at  the  mental  region,  it  would  cause  resorp- 
tion of  the  posterior  wall  of  the  glenoid  cavity,  thus 
permitting  the  condyles  to  recede,  and  articulate  some- 
what posteriorly  to  their  former  positions. 

Through  this  fact,  and  the  change  that  is  brought 
about  at  the  angle  of  the  jaw,  we  are  enabled  to  correct 
one  of  the  most  unsightly  of  dental  deformities.  The 
method  of  procedure  is  well  illustrated  by  a  case  brought 
before  the  Odontological  Society  of  New  York  by  Dr. 
Geo.  S.  Allen.  He  says,  in  part :  "  As  will  be  seen  from 
the  photograph  (Fig.  91),  taken  at  the  time  the  patient 
was  wearing  this  apparatus,  it  consists  of  two  parts. 
For  the  lower  part,  I  made  a  brass  plate  to  fit  the  chin, 
having  arms  with  hooked  ends  reaching  to  a  point  just 
below  the  point  of  the  chin.  These  arms  were  arranged 
in  such  a  way  that  the  distance  between  them  could  be 
altered  at  will  by  simply  pressing  them  apart  or  to- 
gether. The  upper  part  consisted  of  a  simple  network, 
going  over  the  head  and  having  two  hooks  on  each  side, 
one  hook  being  above  and  the  other  below  the  ear. 
When  this  apparatus  was  completed  and  in  use,  there 
were  four  ligatures  of  ordinary  elastic  rubber  pulling  in 
such  a  way  as   to   force  the   lower  jaw  almost  directly 


1 82  DENTAL    PROSTHESIS    AND    METALLURGY. 

backward.  The  work  proceeded  very  rapidly,  so  that  at 
the  end  of  two  months  the  irregularity  was  almost 
entirely  cured." 

A  very  good  method  of  making  the  chin  piece — Dr. 


Fig.  91 


Guilford's  method — is  to  take  a  plaster  impression  of 
the  chin  and  from  this  make  a  model.  The  model  is 
then  overlaid  with  a  piece  of  trial-plate  wax,  from 
which,  after  being  varnished,  a  mold  in  sand  is 
obtained  and  a  die  and  counter-die    made.     Between 


CORRECTION    OF    DENTAL    IRREGULARITIES.  1 83 

these  a  piece  of  soft  and  heavy  brass  plate  is  struck  up 
and  drilled  full  of  holes.  After  fashioning  heavy  piano 
wires  to  cross  the  plate  and  extend  sufficiently  beyond 
to  form  hooks,  they  are  soft  soldered  to  the  brass  plate 
and  the  latter  covered  with  black  silk  with  a  thick  layer 
of  cotton  batting  laid  between  the  two.  The  enlarged 
size  of  the  chin  piece  will  admit  of  this.  The  piece 
thus  padded  will  fit  the  chin  and  be  soft  enough  to  pre- 
vent pain  when  pressure  is  brought  to  bear  upon  it. 

Torsion. — "  The  term    torsion,  as  applied    to  the 
teeth,  signifies  that  condition  in  which  a  tooth  is  found 

Fig.  92. 

Fig.  93. 


to  be  turned  upon  its  axis.  Rotation  refers  to  the  act 
of  twisting  or  turning  a  tooth  so  as  to  bring  it  into  nor- 
mal position.  Torsion,  therefore,  describes  the  condi- 
tion, and  rotation  the  operation."* 

Rotation  by  Rubber  Ring. — In  the  accompanying 
illustration,  Fig.  92,  Dr.  Guilford's  method  of  employ- 
ing bands  and  rubber  rings  for  rotation  is  given. 
Platinum  bands  were  fitted  to  the.  centrals,  with  a  gold 
hook  soldered  to  each  at  points  that  would  furnish  the 
greatest  amount  of  tractile  power.     After  the  bands  were 


*  Guilford's  "  Orthodontia." 


1 84  DENTAL    PROSTHESIS    AND    METALLURGY. 

cemented  in  place  a  rubber  ring  was  stretched  from 
tooth  to  tooth,  in  the  manner  shown  in  Fig.  92.  The 
mal posed  tooth  was  thus  readily  brought  into  contact 
with  its  fellow,  and  at  the  same  time  considerably 
straightened.  After  which  it  was  retained  by  the  retainer 
shown  in  Fig.  93. 

Rotation  by  Spring  Bar. — Where  the  mesial 
angles  protrude  double  rotation  can  be  accomplished  by 
the  very  simple  and  effectual  method  recommended  by 
Dr.  Angle. 

Upon   each  of  the  teeth   to   be  rotated  place  bands 

Fig.  94. 


with  tubes  soldered  to  their  labial  faces  near  the  distal 
angles.  One  tube  is  set  vertically  and  the  other  hori- 
zontally. A  short  piece  of  piano  or  German  silver  wire, 
bent  to  a  right  angle  at  one  end,  is  inserted  in  these 
tubes,  and  rotation  is  effected  by  the  elasticity  of  the 
wire  (Fig.  94).  Once  in  position,  the  teeth  are  retained 
by  inserting  in  the  tubes  a  suitably  shaped  piece  of  non- 
elastic  gold  wire. 

Lack  of  Anterior  Occlusion. — This  form  of 
irregularity  is  fortunately  rare,  as  it  is  one  of  the  least 
amenable  to  treatment.  The  cause  is  usually  the  lack  of 
alveolar   development  in  the  anterior    portion    of  the 


CROWN-    AND    BRIDGE-WORK.  1 85 

mouth,  sometimes  accompanied  with  an  excessive 
growth  in  the  molar  region. 

Treatment. — When  the  deformity  is  slight  it  may 
be  corrected  by  grinding  off  all  the  antagonizing  points 
from  the  posterior  teeth,  which  will  shorten  the  bite, 
bringing  the  anterior  teeth  closer  together.  If  the  third 
molars  were  in  position  and  adding  to  the  trouble  they 
should  be  extracted.  Then,  if  necessary,  one  or  more 
of  the  remaining  molar  teeth  upon  either  side  of  the 
mouth  (those  in  the  poorest  condition  to  be  selected) 
may  be  devitalized,  ground  down  beyond  the  point 
necessary,  and  then  covered  with  gold  crowns. 

Where  considerable  grinding  upon  vital  teeth  is  done 
and  the  exposed  dentine  becomes  quite  sensitive,  it  may 
be  obtunded  by  a  repeated  application  of  either  chlorid 
of  zinc  or  nitrate  of  silver. 


CROWN-  AND  BRIDGE-WORK. 

Preparation    of   the    Root    for    an   Artificial 

Crown. — All  remaining  portions  of  the  natural  crown 
should  first  be  removed  with  suitable  instruments. 
If  the  cervical  portion  of  the  tooth  is  comparatively 
sound  and  unbroken,  this  may  be  most  expeditiously 
accomplished,  and  with  less  risk  of  injury  to  the 
root,  by  cutting  two  parallel  grooves,  opposite  each 
other,  on  the  labial  and  palatal  surfaces,  with  a  small 
circular  saw,  or  a  hard  rubber  or  rubber  and  corun- 
dum disc.  These  grooves  should  be  cut  through  the 
enamel  deep  into  the  dentine.  Then  with  the  excising 
13 


i86 


DENTAL    PROSTHESIS    AND    METALLURGY. 


Fig.  95- 


forceps,  the  cutting  edges  of  which  are  placed  in  the 
groove,  the  crown  is  readily  severed 
from  the  root. 

After  the  use  of  the  discs  and  ex- 
cising forceps,  any  remaining  por- 
tions projecting  beyond  the  free 
margins  of  the  gum  should  be  re- 
moved and  proper  shape  given  to 
the  end  of  the  root.  A  flat-edged 
corundum  stone,  or  what  are  known 
as  the  Ottolengui  root  facers  (Fig. 
95),  are  the  best  for  the  purpose, 
and  when  in  use  the  stones  should 
be  kept  constantly  wet  and  free 
from  clogging  particles  of  tooth  subtance.  The  end  of 
the  root  should  be  dressed  down,  anteriorly,  a  little 
below  the  free  margin  of  the  gum,  care  being  taken  not 
to  cause  unnecessary  laceration  ;  in  this  way  the  artificial 
crown,  when  adjusted  to  the  root,  will  unite  so  inti- 
mately with  the  gum  in  front,  in  ordinary  cases,  as  to 
render  exposure  unnecessary.  The  surface  of  the  root 
prepared  in  this  manner  will  present  a  concavity  corre- 
sponding with  the  festoon  of  the  gum. 

If  a  living  pulp  remains  in  the  root,  it  will  not  ordi- 
narily be  practicable, — unless  there  is  partial  oblitera- 
tion and  consequent  recession  of  the  pulp  cavity  as  the 
result  of  ossific  deposits, — either  to  cut  off  the  tooth  on 
a  line  with  the  gum  or  even  transversely,  or  to  dress 
the  root  even  with  the  gum,  without  inflicting  insuffer- 
able pain.     It  will  be  necessary,  therefore,  under  such 


CROWN-    AND    BRIDGE- WORK.  187 

circumstances,  either  to  devitalize,  and  extirpate  the 
pulp  through  the  carious  opening  in  the  crown  before 
the  latter  is  removed,  or  (if  not  exposed  by  excising  the 
tooth),  through  an  opening  into  the  pulp,  made  with  a 
drill  revolved  by  the  dental  engine,  after  excision. 

Devitalization  of  the  Pulp. — There  are  several 
ways  of  extirpating  a  dental  pulp.  One  of  the  older 
and  still  not  uncommon  methods  of  operating  consists, 
first,  in  devitalizing  it  with  arsenious  acid  and  then  re- 
moving it  with  a  broach.  Another  method  practiced 
by  some  is  to  thoroughly  expose  the  pulp,  apply  co- 
cain,  and  then  extract  the  pulp  with  a  broach. 

Excision  of  Crown  and  Instantaneous  Extir- 
pation of  the  Pulp. — A  somewhat  heroic  method, 
though  one  with  which  several  operators  have  had  much 
satisfaction,  by  which  a  living  pulp  may  be  quickly  and 
successfully  removed,  with  comparatively  little  pain, 
consists  in  cutting  the  labial  and  palatal  grooves  as  has 
been  directed,  making  them  as  deep  as  possible,  without 
inflicting  too  much  pain  ;  then  with  the  excising  forceps, 
the  cutting  edges  of  which  are  inserted  in  these  grooves, 
the  crown  is  quickly  severed  from  the  root.  This 
usually  leaves  the  pulp  fully  exposed  and  paralyzed, 
when  a  piece  of  orange  wood  —  previously  cut  and 
shaped  to  about  the  size  of  the  canal,  not  larger,  and 
the  point  saturated  with  carbolic  acid — is  carefully 
placed  against  the  exposed  point  of  the  pulp  and 
quickly  driven  with  one  light  blow  from  the  mallet  into 
the  pulp  canal.  When  the  wood  is  withdrawn,  the  pulp 
often  adheres  to  it ;  if  not,  it  may  be  quickly  removed 


DENTAL   PROSTHESIS   AND    METALLURGY. 


with  a  broach.     In  this  operation  the  immediate  paraly- 
sis induced  renders  it  comparatively  painless. 

Preparation  of  the  Pulp  Canal. — After  the  re- 
moval of  the  pulp  the  apical  foramen  should  be  thor- 
oughly closed  by  any  method  usually  employed  in  root 
filling.  A  neglect  of  this  important  measure  will 
greatly  endanger  the  success  of  the  operation. 

The  proper  treatment  and  preparation  of  the  root 
having  been  thus  far  accomplished,  the  canal  of  the 
latter  should  next  be  enlarged  for  the  recep- 
tion of  a  dowel-pin.  This  is  effected  with 
an  ordinary  fissure  drill  or  the  Ottolengui 
root  reamers  (Fig.  96). 

The  natural  opening  in  the  root  should 
be  enlarged  to  the  depth  of  two  or  more 
lines,  according  to  the  length  of  the  root ; 
and  the  orifice  should  be  made  large 
enough  to  admit  a  support  of  sufficient  size 
to  secure  the  crown  firmly  in  position.  The 
direction  of  the  drill  in  cutting  should 
follow  closely  that  of  the  natural  canal  in 
the  root,  since  but  a  slight  deviation  in  this  respect  may 
endanger  the  integrity  of  the  latter  by  too  great  a 
thinning,  or  actual  perforation,  of  its  walls.  The  face 
of  the  root  should  then  be  given  a  suitable  shape  for 
the  reception  of  the  form  of  crown  to  be  attached, 
the  methods  of  fitting  and  inserting  which  will  now 
be  considered,  the  simple  or  all-porcelain  system  being 
first  taken  up. 

Porcelain    Crowns.  —  The    porcelain    crown    is 


CROWN-    AND    BRIDGE- WORK.  1 89 

especially  useful  where  an  inexpensive  and  quickly 
adjusted  crown  is  necessary  ■  or  where  some  path- 
ological condition  would  seem  to  limit  the  probable 
permanency  of  an  operation,  or,  again,  where  a  tem- 
porary crown  is  desired,  to  serve,  as  is  sometimes  neces- 
sary, until  the  patient  or  operator  can  make  suitable 
engagements  for  more  permanent  work.* 

THE  FERRULE  OR  COLLAR  CROWN. 

This  crown  was  originally  brought  to  the  notice  of 
the  profession  by  Dr.  C.  M.  Richmond,  of  New  York, 
and  is  therefore  ordinarily  known  as  the  Richmond 
Crown.  Numerous  modifications  have  been  made,  how- 
ever, which  enhance  its  value.  The  process  of  con- 
structing the  improved  crown  is  as  follows : — 

Facing  the  Root. — The  root  must  be  trimmed 
down  to  about  the  gum-line,  except  the  labial  portion, 
which  should  be  cut  nearly  a  sixteenth  of 
Fig.  97.  an  mch  below  the  gum  margin.  For 
this  purpose,  carborundum  stones  or  the 
Ottolengui  root-facers  are  employed,  as 
described  on  page  186. 

Removing  the  Enamel  Ledge. — 

The  ring  of  enamel  remaining  upon  the 

root  should  be  carefully  and  thoroughly 

removed   (see  Fig.   97),  making  the  sides  of  the  root 

parallel,  so  that  the  band,  when  applied,  mayyf/  closely 


*  For  full  instructions  in  mounting  this  form  of  crown  see  Rich- 
ardson's Mechanical  Dentistry,  6th  Ed. 


190 


DENTAL    PROSTHESIS    AND    METALLURGY. 


its  entire  width.  If  this  is  not  done,  the  band,  even  if 
a  narrow  one,  instead  of  fitting  closely  will  form  a 
pocket  beneath  the  gum  margin,  and  will,  in  consequence 
of  its  irritating  effect  upon  the  surrounding  tissues, 
cause  more  or  less  inflammation  and  possibly  the  loss 
of  the  root. 

Numerous  instruments  have  been  devised  for  the  re- 


FlG 


moval  of  this  enamel ;  among  the  most  efficient  are 
those  invented  by  Dr.  Calvin  S.  Case  and  Dr.  Geo.  M. 
Weirich.  Fig.  98  illustrates  Dr.  Case's  enamel  cleavers. 
These  are  so  shaped  that  they  can  be  partially  rotated 
under  the  margin  of  the  gum,  presenting  a  sharp  point 
toward  portions  of  the  enamel  that  will  not  easily  clean 
off,  with  a  view  to   fracturing  it  as  the  diamond  cuts 


CROWN-    AND    BRIDGE-WORK.  191 

glass,  breaking  it  up  into  small  pieces  which  can  readily 

Fig.  99. 


be  detached  and  the  sides  straightened  and 
smoothed  by  the  broad  blade.  The  peculiari- 
ties of  shape  are  shown  in  the  enlarged  cuts. 

The  Weirich  cleaver,  or  chisel,  is  shown  in 
Fig.  99.  With  this  instrument  and  a  few 
gentle  blows  from  the  mallet  the  enamel  is 
readily  broken  up  and  detached.  The  rubber 
cushion  in  the  center  of  the  chisel  takes  up 
the  blow,  thus  relieving  the  root  from  unneces- 
sary shock.  In  the  accompanying  illustration 
the  instrument  is  shown  in  place  ready  to  re- 
ceive the  blow  from  the  mallet.  It  is  a  well- 
known  fact  that  with  most  of  the  appliances  on 
sale  it  is  difficult  to  properly  remove  the 
enamel  from  the  approximal  surfaces  of  roots, 
especially  where  they  are  very  close.  With 
this  instrument  (to  be  followed  with  the  ordi- 
nary cervical-wall  chisel  or  the  Chase  cleavers) 
the  root  upon  all  sides   can  be  readily  and    properly 


I92  DENTAL    PROSTHESIS    AND    METALLURGY. 

prepared  for  the  reception  of  a  band  or  collar  with 
very  little  discomfort  to  the  patient  or  trouble  to  the 
operator. 

Taking  Measurement  of  the  Root. — After  the 
enamel  has  been  thoroughly  removed,  an  accurate 
measurement  of  the  neck  of  the  root  should  be  secured. 
Several  instruments  have  been  devised  for  this  pur- 
pose; one  of  the  simplest  and  most  convenient  is  the 

Fig. 100. 


one  suggested  by  Dr.  Geo.  M.  Weirich,  which  is  shown 
in  Fig.  100. 

Transferring  Measurement  to  the  Banding 
Material. — In  order  to  transfer  this  measurement  accu- 
rately to  the  banding  material,  cut  the  wire  loop  in  the 
center  and  spread  the  ends  in  opposite  directions,  as 
shown  in  Fig.  101.  It  is  then  laid  on  the  piece  of 
gold  to  be  used  for  the  band  (which  should  be  22  k. 
and  about  30  gauge) ;    this   should  be   cut  the  exact 


CROWN-    AND    BRIDGE-WORK.  193 

lengtli  of  the  wire,  and  about  an  eighth  of  an  inch  in 
width,  unless  for  special  reasons  it  is  necessary  to  have 
it  wider.     This  small  strip  of  gold  should  now  be  an- 
nealed  over  a  lamp  or  Bunsen   burner, 
then    with    round-nosed   pliers    brought        Fig.  ioi. 
into  a  circular  form,  and  with    the  fin- 
gers the  ends  should  be  carefully  pressed 
by  each  other.     This  will  form  a  slight 
kink  in  the  band,  so   that  the   ends,  if 
now  gently  drawn  apart  and  let  go,  will 
spring  accurately  together  ready  for  sol- 
dering, a  butt-joint  being  stronger  and 
for  obvious  reasons  preferable  to  a  lap- 
joint. 

Soldering  the  Band. — In  soldering  the  band,  a 
corner  of  the  two  edges  should  be  grasped  with  the 
soldering  pliers,  the  joint  should  then  be  slightly  coated 
with  borax,  and  a  small  piece  of  20  k.  solder  placed 
over  it,  on  the  outside  of  the  band  (see  Fig.  102).  It 
should  then  be  held  in  the  flame  of  a  Bunsen  burner 
until  the  solder  flows,  at  which  time  it  must  be  in- 
stantly removed.  With  a  little  experience  and  care  in 
soldering  in  this  way  (over  a  Bunsen  burner),  it  can  be 
done  more  conveniently,  in  less  time,  and  with  much 
less  danger  of  burning  the  band,  than  with  the  blow- 
pipe. 

Fitting  Band  to  the  Root.— The  band  is  now 
ready  to  be  fitted  or  adjusted  to  the  root.  If  the  end 
of  the  root  is  not  round,  as  is  usually  the  case,  the  sides 
of  the  band  can  be  flattened  or  otherwise  shaped  with 


194 


DENTAL    PROSTHESIS    AND    METALLURGY. 


slight  pressure  from  the  thumb  and  finger  or  with  suit- 
able pliers.  The  upper  border  should  then  be  trimmed 
to  conform  to  the  shape  of  the  process  or  the  line  of  the 
gum-attachment ;  in  many  cases,  unless  the  band  is 
greatly  depressed  or  cut  out  on  the  sides,  it  will  be  found 
that  the  gum  will  be  detached  from  the  sides  of  the  root, 
and  that  the  process  will  be  reached  before  the  root  is 
covered  high  enough  on  the  labial  and  palatal  surfaces. 
Place  the  band  thus  shaped  upon  the  root,  and  if  the 
measurement  and  each  progressive  stage  have  been  ac- 
curately performed,  it  will  be   found  to  fit  perfectly. 


Fig.  102. 


11 


Now  press  or  drive  it  up  carefully,  until  the  point  of 
attachment  between  the  soft  tissues  and  the  root  are 
reached  (about  one-sixteenth  of  an  inch  beyond  the 
gum  margin),  which  is  shown  by  the  slight  whitening  of 
the  gum.  When  this  is  very  marked  upon  any  side,  the 
band  should  be  removed  and  relieved  by  cutting  it  away 
at  that  point,  and  then  readjusted.  A  corundum-wheel 
is  now  gently  passed  over  the  labial  portion  of  the 
lower  edge  of  the  band,  to  level  it  with  the  face  of  the 
root  and  to  render  the  band  invisible  when  the  crown  is 
finished.  In  doing  this  the  wheel  used  should  be  re- 
volved toward  the  root,  so  it  will  not  irritate  the  soft 
tissues,  as  it  would  were  the  force  applied  in  the  oppo- 


CROWN-    AND    BRIDGE-WORK.  1 95 

site  direction, — and  at  the  same  time  it  will  turn  the 
feather-edge  of  metal  over  the  end  of  the  root. 

Forming  the  Base  Plate. — Cut  a  piece  of  gold 
(32  to  34  gauge)  of  suitable  length  and  width,  anneal, 
and  then  press  it  against  the  lower  edge  of  the  band  with 
the  fingers  until  it  is  nicely  adapted ;  secure 
it  in  this  position  for  soldering  by  three  or 
four  strands  of  wire,  as  shown  in  Fig.  103. 
Now  paint  the  joint  with  borax  dissolved  in 
water,  lay  a  small  piece  of  20  k.  solder 
against  the  back  or  palatal  portion  of  the  band,  on  the 
outside,  and  hold  it  in  the  flame  of  a  Bunsen  burner  until 
the  solder  flows,  which  will  be  seen  to  run  entirely 
around  the  band,  uniting  it  with  the  base  plate  at  every 
point.  The  surplus  of  the  base  plate  material  should, 
with  shears  and  corundum  or  carborundum-stone,  be 
trimmed  off  flush  with  the  band,  the  two  now  forming 
a  complete  cap  for  the  face  and  sides  of  the  root. 

Fitting  the  Pin. — The  next  step  is  the  preparation 
and  adjustment  of  a  pin  through  the  cap  into  the  root 
canal.  The  canal  should  be  enlarged  toward  the  palatal 
side  of  the  root;  this  will  give  more  room  when  we 
come  to  grind  the  tooth,  and  at  the  same  time  secure 
the  greatest  attainable  strength  when  the  crown  is  com- 
pleted. 

The  base  plate  of  a  cap  is  perforated  at  a  point 
directly  over  the  opening  into  the  canal.  This  may  be 
done  with  a  plate  punch  and  enlarged  to  suit  the  case 
with  a  burr  on  the  dental  engine.  A  pin  of  platinum 
wire,  number  16  or  17,  standard  gauge,  should  now  be 


I96  DENTAL    PROSTHESIS    AND    METALLURGY. 

slightly  tapered  at  the  end  and  passed  through  the 
aperture  made  in  the  cap  and  up  into  the  root  canal. 
The  end  of  the  pin  projecting  below  the  cap  may  be 
marked,  withdrawn,  and  bent  at  a  right  angle,  so  that 
it  will  point  away  from  the  tooth,  that  is,  toward  the 
palatal  surface;  it  may  then  be  waxed  in,  invested, 
and  soldered  with  the  tooth,  or  invested  and  soldered 
at  this  stage,  and  the  surplus  of  pin  and  solder  brought 
down  flush  with  a  file  or  stone. 

Grinding  and  Fitting  the  Tooth. — The  cap  and 

pin   should  be   readjusted    to  the  root.     A  plain-plate 

tooth, *   of    suitable    form  and    color,    is   now   ground 

and  fitted  to  the  cap.     The  labio-cervical  edge  of  the 

tooth  (a,  Fig.  104)  should  be  so  ground  that 

Fio.  104.  . 

it  will  be  flush  with  the  edge  of  the  band 
and  meet  the  margin  of  the  gum.  It 
should  also  be  ground  out  at  the  center  of 
the  base  (b),  so  as  to  form  a  slight  space 
just  over  the  base  of  the  pin. 

The  tooth  is  then  backed  with  either  thin 
platinum   or  gold-plate  (gold  will  give  a  slight  yellow 

*  Many  writers  advise  using  cross-pin  teeth ;  it  is  self  evident, 
however,  that  in  this  work  straight-pin  teeth  should  be  employed  and 
the  cross-pins  avoided  wherever  possible,  for  the  same  reasons  as 
given  under  plate  work:  (1)  The  position  of  the  pins  weakens 
the  body  of  the  tooth.  (2)  Their  position  makes  the  strain  upon 
the  tooth  greater,  as  it  gives  increased  leverage  between  the  pins 
and,  the  cutting  edge.  (3)  There  is  more  liability  of  cracking 
the  teeth  in  soldering,  on  account  of  so  much  metal  being  brought 
at  one  point. 


CROWN-    AND    BRIDGE  WORK.  197 

shade  to  the  tooth  while  platinum  will  give  a  bluish  tint). 
The  upper  edge  of  the  backing,  brought  down  thin 
with  a  file  or  stone,  should  extend  as  far  as  possible  under 
and  between  the  tooth  and  the  cap,  so  that  the  solder 
will  more  readily  flow  in  and  fill  what  space  there  may 
be.  The  incisive  edge  of  the  backing  should  also  be 
brought  slightly  over  the  edge  of  the  porcelain  (though 
it  is  not  so  shown  in  the  accompanying  illustration), 
this  portion  of  the  tooth  being  previously  beveled  with 
a  fine  stone.  In  this,  the  possibility  of  breaking  the 
tooth  from  the  force  of  mastication  is  much  dimin- 
ished. 

Waxing  the  Tooth  in  Position. — A  perfect  joint 
and  the  proper  length  and  angle  of  the  tooth  having 
been  secured,  the  pieces,  that  is,  the  tooth,  cap,  and 
pin,  should  now  be  thoroughly  dried,  then  held  to- 
gether in  the  proper  relationship,  and  secured  in  this 
position  by  running  warm  adhesive  (resin)  wax  over  the 
palatal  portion  of  the  tooth,  attaching  the  backing  to 
the  cap.  It  should  then,  before  the  wax  gets  very  hard, 
be  carefully  carried  to  position  upon  the  root,  when  any 
correction  in  the  position  of  the  tooth  can  readily  be 
made.  Now  apply  a  little  cold  water  from  the  syringe 
or  on  a  pledget  of  cotton ;  this  will  harden  the  wax,  so 
that  the  crown  may  be  removed  without  changing  the 
position  of  the  tooth  upon  the  cap.  It  will  then  be 
ready  to  be  invested  for  soldering. 

Investing. — A  most  suitable  investment  for  crowa 
work  is  marble-dust  and  plaster,  equal  parts,  with  a 
small  quantity  of  fine  asbestos  fiber  thoroughly  incor- 


I98  DENTAL    PROSTHESIS   AND    METALLURGY. 

porated.  After  the  investment  has  thoroughly  set,  the 
wax  may  be  removed  and  the  surface  of  the  backing 
and  cap  cleansed  by  directing  upon  it  a  small  stream  of 
boiling  water.  The  investment  should  be  cut  away  so 
as  to  expose   the  sides  of  the  backing  and   the  lower 

border  of  the  band,  as  illustrated 

FlG-  ios-  in  Fig.  105,  but  every  portion  of 

*~\^  the  porcelain  should  be  protected. 

/^^^^^T^k  Soldering  and  Finishing. — 

/"■  \-'CM  A        %     The  case  snom1d  then  be  at  first 

I      sf       .'  ||    gently  heated  up  to  drive  off  the 

^HL,     ._.. J#    moisture,  then  transferred  to  the 

soldering  block,  when,  with  the 
blowpipe,  more  heat  should  be  applied,  continuously  at 
first,  until  the  investment  and  tooth  are  thoroughly  and 
evenly  heated  throughout.  Gold  solder,  18  k.,  is  then 
cut  in  small  pieces  and  placed,  with  a  little  borax,  over 
the  aperture  between  the  backing  of  the  tooth  and  the 
cap.  The  investment  being  now  uniformly  heated,  the 
flame  from  the  blowpipe  should  be  directed  upon  the 
solder,  mostly  in  the  direction  indicated  in  Fig.  105, 
when,  if  the  entire  case  has  been  previously  brought  to 
a  red  heat,  the  solder  will  readily  melt  and  flow  between 
the  tooth  and  cap.  Additional  solder  should  now  be 
added  and  melted  until  the  proper  contour  of  the  tooth 
is  insured. 

The  tooth  and  investment  should  then  be  placed  in 
and  covered  with  sand,  plaster,  or  some  other  suitable 
substance  to  keep  the  heat  from  radiating  too  rapidly 
and    thus  cracking   the   tooth.     It   should   be   left   so 


CROWN-    AND    BRIDGE-WORK. 


I99 


Fig 


covered  until  it  is  thoroughly  cool.  We  might  add 
here,  that  it  is  well  to  direct  the  flame  from  the  blow- 
pipe into  the  sand  or  other  material  for  a  moment  before 
placing  the  tooth  in.  After  the  tooth  is  thoroughly 
cool,  the  investment  may  be  broken  away,  and  all  oxi- 
dation and  borax  removed  by  placing  it 
for  a  few  minutes  in  the  acid  bath.  The 
crown  is  then  ready  to  be  finished  and 
polished.  The  shaping  of  the  solder  can 
best  be  done  with  carborundum  stones, 
followed  with  hard-rubber  discs,  and  then 
fine  sand-paper  or  cuttlefish  discs,  while 
the  polishing  is  accomplished  with  brush 
and  buff-wheels,  pumice  stone,  whiting, 
and  rouge.  The  completed  crown  in  position  is  shown 
in  Fig.  106. 


THE  RICHMOND  METHOD   APPLIED   TO 
BICUSPID  ROOTS. 

The  capping  of  the  root  is  similar  to  that  already 
described ;  the  crown  will  have  greater  strength,  how- 
ever, if  a  portion  of  the  palatal  section  of  the  natural 
crown,  when  strong  enough,  is  retained,  and  the  band 
made  deep  enough  to  cover  it.  One  pin  is  all  that 
is  usually  required,  and  where  there  are  two  distinct 
canals,  the  palatal  should  be  used  to  receive  the  pin ; 
thus  greater  strength  is  secured  at  the  point  where  it 
is  most  needed,  and  the  pin  is  so  located  that  it 
will  not  interfere  with  the  grinding  and  adjusting  of 
the  tooth.     The  cap  and  pin  being  in  position,  a  suit- 


200 


DENTAL    PROSTHESIS    AND    METALLURGY. 


Fig.  107. 


able  cuspid  tooth  or  bicuspid  facing  is  then  ground, 
backed,  and  adjusted  to  represent  the  labial  aspect,  and 
then  properly  secured  to  the  cap  with  adhesive  wax. 
The  tooth,  cap,  and  pin  are  then  carefully  removed, 
invested,  and  soldered ;  after  which  they  are  again 
placed  upon  the  root,  and  the  occluding  edge  of  the 
tooth  is  ground  clear  of  the  antagonizing  teeth  at 
about  the  angle  shown  at  A,  Fig.  107. 

From  a  suitable  die  or  die-plate  (see   page  206)  the 
cusps  or  occluding  surface  of  the  tooth  is  swaged  from 
22  k.  gold  plate.     These  cusps  should  then  be 
filled   in    with  20  k.    plate   or   solder.      This 
is  done  by  cutting  the  gold  into  small  pieces, 
and  placing  them,  with  a  little  borax,  in  the 
depressions  of  the  cusps,  all  of  which  is  held 
over  a  Bunsen  burner  until  the  small  pieces  are 
melted,  when  they  will  flow  into  these  depres- 
sions and  fill  them  level  full.     The  surplus  is 
trimmed  away,   the   cusps  ground   and   fitted 
to  the  edge  of  the  porcelain,   in  position   to 
secure  proper  occlusion   (Fig.  108),  and  secured  with 
wax  as  shown  at  A. 

A  piece  of  thin,  pure  gold  plate  or  mica 
is  then  adjusted  on  each  side  of  the  crown 
(B,  Fig.  108),  the  surfaces  of  which,  if 
dry  and  slightly  warm,  will  be  held  in  posi- 
tion temporarily  by  pressing  them  gently 
against  the  side  of  the  wax.  This  is  all 
now  invested  together  (Fig.  109). 

The  long  ends  of  these  side  pieces,  after  being  in- 
vested, hold  them  in  position,  as  the  investment  should 


Fig 


CROWN-    AND    BRIDGE-WORK. 


20I 


be  cut  away  so  as  to  expose  the  sides  of  the  crown  as 
shown  at  A,  Fig.  109.  In  the 
process  of  soldering,  after  the 
case  has  been  properly  heated, 
the  small  pieces  of  solder 
and  borax  are  placed  in  the 
aperture  formed  by  these 
sides  of  gold  or  mica  (the 
place    formerly   filled    with 

wax),  and  the  flame  from  the  blowpipe  directed  cau- 
tiously against  these  exposed  sides  (A).  The  solder 
will  then  flow,  uniting  the  several  parts,  when  more 
should  be  added  until  the  proper  contour  with  perfect 
continuity  of  structure  is  secured.  The  crown  can  be 
made  without  the  gold  or  mica  sides  if  great  care  is 
exercised  in  flowing  the  solder.  There  will  be  more 
surplus  solder,  however,  to  be  finished  off. 

In  finishing,  the  solder  is  brought  to  the  contour  of  a 
bicuspid  tooth  with  stones  and  sand-paper 
discs,  when  it  is  ready  for  the  polishing  pro- 
cess. The  finished  crown  is  represented  in 
place  upon  the  root  in  Fig.  no. 

Other  Methods. — There  areother  methods 
practised,  and  though  some  of  them  may  not 
be  as  artistic  as  the   one  just  described,  they 
are  much  simpler  and  quicker.     For  instance, 
the  palatal  cusp   may  be  built  up  with  several 
pieces  of  gold  plate — previously  melted  into  the  form 
of  balls  and  flattened  out  with  a  hammer.     The  back- 
ing is  brought  down    and   closely  burnished  over  the 
14 


Fig.  iio. 


20  2  DENTAL    PROSTHESIS    AND    METALLURGY. 

cutting  edge  of  the  tooth,  which  is  then  waxed  in 
position,  tried  in  the  mouth,  and  invested,  and  when 
ready  to  be  soldered,  these  flattened  pieces  of  gold  are 
laid  in  position,  united,  and  filled  in  with  18  k.  solder, 
which  is  also  brought  over  the  backing  to  the  tip  of  the 
tooth.  This  plate  and  solder  are  afterward  brought  to 
the  proper  shape  and  contour  with  the  stones  and  discs. 

Then,  again,  the  palatal  portion  of  the  band  is  ex- 
tended down  so  as  to  nearly  touch  the  antagonizing 
tooth.  This  leaves  only  a  comparatively  small  space  to 
be  filled  in  with  solder,  which  is  afterward  trimmed  and 
finished  to  the  form  of  the  crown. 

Or,  a  method  that  the  author  often  employs  is  to 
back  the  tooth,  grind  off  or  bevel  the  occluding  surface, 
and  then  joint  and  adjust  the  prepared  gold  cusps ;  wax 
them  in  position,  invest,  and  flow  in  sufficient  20  k. 
solder  to  hold  them  securely  in  position,  after  which  the 
tooth  maybe  ground,  adjusted,  and  soldered  to  the  cap, 
as  has  been  directed.  One  advantage  of  this  method 
is,  that  different  forms  and  shades  of  bicuspid  facings 
may  be  so  prepared — with  gold  occluding  surfaces — and 
kept  in  stock;  and  again,  in  the  latter  three  methods, 
as  may  be  seen,  it  is  only  necessary  to  invest  the  cap 
once  after  adjusting  the  tooth. 

THE   DOWNIE   CROWN. 
In  this  crown  we  have  a  combination  of  the  all-porce- 
lain crown  with  a  band  or  ferrule.     The  root  is  prepared 
and  measurement  taken  as  has  just  been  described  for 
the  Richmond  crown. 


CROWN-    AND    BRIDGE-WORK.  203 

Making  the  Band. — The  band  is  made  from  plat- 
inum, a  strip  of  which  of  sufficient  length  and  width  is 
soldered  with  pure  gold.  The  band  is  now  adjusted  and 
fitted  to  the  root,  allowing  a  narrow  margin  to  extend 
below  its  end.  Remove  the  band  and  cut  small  V- 
shaped  spaces  in  its  lower  border, 
which,  when  the  band  is  replaced  in  FlG-  "*■  FlG-  II2- 
position,  will  allow  the  points  to  be 
bent  down  over  the  root.  Fig.  in 
shows  the  band  thus  prepared.  pc^fe 

Preparing  the  Tooth. — Select  a 
suitable  plain,  cross-pin  tooth,  take 
square  iridio-platinum  wire  of  suffi- 
cient size  for  post,  taper  one  end  and  flatten  the  other 
with  a  hammer,  file  notch  in  each  side,  and,  placing  be- 
tween pins,  bend  them  over  as  in  Fig.  112.  If  the  bite  is 
close,  grind  pins  down  to  give  sufficient  room  for  the 
body.  After  fitting  the  tooth  to  position, by  bending  post, 
if  necessary,  or  grinding  base  of  tooth,  dry  the  root  and 
adjacent  parts,  and  warming  a  small  pellet  of  sticky 
wax,  place  it  on  end  of  band,  which  is  in  position  on 
the  root,  and  force  post  through  it  and  press  tooth  up 
to  position.  Now  bring  wax  up  against  the  back  of  the 
tooth  and  see  that  the  articulation  is  correct.  Carefully 
remoye  all  together  by  loosening  band  with  hoe-shaped 
excavator.  Remove  wax  from  around  post  where  it 
has  drawn  inside  of  the  band.  Mixsilex  and  plaster,  in 
the  proportion  of  two  parts  of  plaster  to  three  parts 
silex,  and  fill  the  band  with  the  investment,  building  up 
slightly  around   the  post.     After  investment  sets,  boil 


204 


DENTAL    PROSTHESIS    AND    METALLURGY. 


out  the  wax.  Fig.  113  shows  the  tooth  with  investment 
in  band  and  wax  removed. 

Applying  the  Body. — Back  up  with  porcelain  body 
and  put  in  the  furnace*  and  fuse.  Add  more  body, 
building  up  over  anterior  surface  of  band  to  conceal  it, 
and  fuse  again.  We  now  have  a  finished  crown,  as 
shown  in  Fig.  114. 

In  baking,  the  crown  is  placed  in  a  small  tray  or 
slide,  as  shown  in  Fig.  115,  putting  post  through  a  hole 
in  back  end  of  tray,  face  up.     This  prevents  the  tooth 


Fig.  114. 


Fig.  115. 


being  fused  on  to  the  tray,  as  it  rests  only  on  the  back 
of  the  band,  being  held  up  by  the  post,  and  the  body 
not  being  built  up  over  the  posterior  part  of  band. 

Ordinary  teeth  for  vulcanite  work  can  be  used  in 
making  this  crown  if  desired.  When  they  are  used  the 
post  should  be  soldered  between  pins  with  pure  gold. 


THE  ALL-GOLD  CROWN,  OR  CAP. 

In  the  construction  of  the  all-gold  crown,  the  sides 
of  the  natural  crown  and  neck  of  the  tooth  are  brought 


*  The  Downie  or  Sharp  furnace  are  either  well  adapted  for  this 
purpose. 


CROWN-    AND    BRIDGE-WORK. 


205 


down  to — or  a  little  smaller  than — the  size  of  the  root. 
This  is  best  accomplished  by  the  use  of  diamond  discs 
and  small  carborundum-stones  on  the  dental  engine. 
From  the  occluding  surface,  if  any  of  it  remains,  a 
sufficient  amount  should  be  ground  away,  and  the  edges 
slightly  rounded,  to  allow  the  introduction  of  the  gold 
cusps.  The  measurement  and  making  of  the  band  is 
the  same  as  described  in  connection  with  the  Rich- 
mond collar   crown  (see  page    192),  excepting  in  the 


Fig.  116. 


width  of  the  ferrule.  This  should  extend  from  the 
root,  below  the  gum-margin,  to  within  a  line  of  the 
occlusion  with  the  antagonizing  teeth.  After  solder- 
ing and  adjusting,  the  band  should  be  shaped  and  con- 
toured with  burnishers  and  suitable  pliers.  Those  de- 
signed by  Dr.  Eugene  Pettit  are  the  most  practical  that 
have  yet  been  placed  upon  the  market  for  this  pur- 
pose. They  are  shown  in  Fig.  116.  The  surface  of 
the  band  to  which  the  cusps  are  to  be  attached  should 
then  be  brought  down  perfectly  smooth  and  flat  with  a 


206 


DENTAL    PROSTHESIS    AND    METALLURGY. 


fine  file  ;  readjusted  carefully  to  the  root,  to  make  sure 
that  it  has  not  been  so  distorted  by  the  different  man- 
ipulations that  it  will  not  pass  readily  to  place  and  fit 
the  root  perfectly  at  every  point.  Finding  all  correct, 
the  next  step  is  making  the  cusps. 

Making  the  Cusps,  or  Occluding  Surface. — A 
number  of  methods  have  been  put  forward  for  making 
gold  cusps.    The  two  that  have  proven  most  satisfactory 

Fig.  117. 


are  the  use  of  separate  dies  and  by  means  of  the  die 
plate.  In  the  former  the  gold  plate  is  placed  upon  a 
piece  of  lead  and  the  die  carefully  driven  into  it,  while 
in  the  latter  method  the  plate  is  laid  over  the  die  de- 
sired and  the  hub  or  small  piece  of  lead  is  driven  down 
into  the  depression.  This  method  is  shown  in  Figs. 
117,  118,  and  119. 

Fig.  117  shows  a  section  of  the  die  plate  with  a  piece 
of  gold  plate  over  the  upper  right  first  molar,  and  the 


CROWN-    AND    BRIDGE-WORK. 


207 


lead  hub  ready  to  be  driven  home.  Fig.  118  shows 
the  appearance  after  driving  the  lead,  while  in  Fig.  119 
we  have  the  appearance  of  the  cusps  swaged  into  the 


Fig.  n8. 


^C^iHPflM 


gold  as  well  as  the  lead  after  they  are  removed  from  the 
die  plate. 

Reinforcing  the  Cusps. — After  securing  a  well-de- 


Fig.  119. 


fined  occluding  surface  or  cameo  for  the  case  in  hand, 
it  should  be  filled  with  gold  plate  scraps  or  solder  of  a 
lower  carat,  with  a  little  borax.     This  is  all  held  over  a 


2o8  DENTAL   PROSTHESIS   AND    METALLURGY. 

Bunsen  burner  until  the  small  pieces  of  gold  come  to 
the  fusing  point  and  settle  down  into  the  depressions  of 
the  shell.  More  small  pieces  should  then  be  added  until 
it  is  level  full.  The  surplus  gold  should  then  be  trimmed 
away,  and  a  file  passed  several  times  over  the  surface  of 
the  solder  to  bring  it  down  perfectly  level  and  smooth. 
This  is  all  illustrated  in  Fig.  120. 

Before  removing  the  band  from  its  position  in  the 
mouth,  a  small  mark  should  be  made  with  an  excavator 
to  indicate  the  center  of  the  buccal  surface,  which  will 
serve  as  a  guide  for  the  correct  placement  of  the  cusps. 

Fig.  120. 


By  giving  the  band  and  the  cusps  a  smooth  surface  with 
a  fine  file,  as  has  been  directed,  it  will  be  found  that  an 
accurate  joint  between  them  can  readily  be  secured. 

Adjusting  and  Soldering. — Having  carefully  noted 
the  line  of  occlusion  and  marked  the  band  to  indicate 
the  point  where  the  center  of  the  buccal  surface  of  the 
cusps  or  crown-plate  should  be  placed  and  soldered,  the 
two — the  band  and  the  crown-plate — should  be  carefully 
brought  together  and  secured  with  a  few  strands  of  small 
binding  wire.  The  joint  should  now  be  coated  with 
borax  dissolved  in  water,  when  it  is  ready  for  the  final 
soldering.  If  solder  has  been  used  in  filling  the  cusps, 
no  additional  solder  will  be  needed  at  this  time,  as  by 


CROWN-    AND    BRIDGE-WORK.  20Q 

simply  holding  the  crown  over  the  flame  of  a  Bunsen 
burner  until  the  solder  is  seen  to  come  to  the  fusing 
point  (when  it  should  be  instantly  withdrawn),  it  will 
all  be  united  perfectly.  If,  however,  gold  plate  has 
been  used  entirely  in  forming  the  crown-plate,  a  small 
piece  of  solder  will  be  needed  to  unite  them. 

The  crown  is  now  ready  for  the  finishing  processes, 
which  consist  in  filing  or  grinding  off  the  projecting 
edges  of  the  crown-plate  flush  with  the  face  of  the 
crown,  and  smoothing  and  beveling  the  free  edge 
of  the  band  or  ferrule ;  the  crown  should  then  be  ad- 
justed to  the  root  and  the  occlusion  noted.  If,  as  is 
frequently  the  case,  a  little  of  the  gold  needs  to  be  re- 
moved at  one  or  more  points,  in  order  to  have  a  perfect 
occlusion,  it  should  be  done  with  a  small,  flat-faced 
carborundum-stone.  The  crown  should  then  be  re 
moved  and  polished  at  the  lathe. 


BRIDGE-WORK. 

As  we  have  previously  written  upon  this  subject  (see 
Richardson's  Mechanical  Dentistry),  bridge-work,  to  the 
skilled  dentist  with  experience  in  crown-work,  does  not 
present  any  great  difficulty,  inasmuch  as  crowns  are  the 
beginning  and  the  end ;  it  is  practically  continuous 
crown-work,  though  many  of  the  crowns — those  filling 
or  bridging  the  space  where  the  roots  have  been  re- 
moved— have  neither  collars  nor  posts.  In  construct- 
ing these  teeth,  the  matter  of  cleanliness  should  especi- 
ally be  considered  ;  where  it  is  admissible  to  allow  them 


2IO  DENTAL    PROSTHESIS    AND    METALLURGY. 

to  come  in  contact  with  the  gum-tissue  (as  in  the  an- 
terior part  of  the  mouth),  only  the  cervical  porcelain 
tips  should  touch.  The  metallic  backing  and  solder 
should  recede,  leaving  self-cleansing  spaces. 

Limitations. — For  the  support  of  bridge-dentures 
strong,  healthy  roots  are  required,  and  the  width  of  the 
space  to  be  spanned  must  be  governed  by  the  size  and 
strength  of  these  points  of  anchorage.  Whether  a  full 
upper  or  lower  denture  can  be  supported  by  four  points 
of  attachment  depends  upon  the  relative  smallness  of 
the  jaw,  the  size  and  strength  of  the  roots  and  teeth, 
and  the  occlusion,  the  operator  always  being  governed 
by  the  exact  condition  of  individual  cases.  For  instance : 
One  strong  central  root  will  support  two  teeth,  that 
is,  the  crown  and  either  the  adjoining  central  or  lateral. 
Two  central  roots  will  support  the  four  incisors.  Two 
strong  cuspid  roots  alone,  or  with  the  aid  of  a  central 
root,  will  support  the  six  anterior  teeth.  A  cuspid  root 
and  a  strong,  healthy  second  or  third  molar  on  the 
same  side  will  support  the  intervening  teeth.  One 
molar  or  bicuspid  on  one  side,  and  a  bicuspid  or  molar 
on  the  other,  with  one  or  two  central  roots,  will  support 
a  bridge  between  them.  One  right  and  one  left  molar, 
with  the  assistance  of  the  two  cuspid  roots,  when  the 
conditions  are  favorable,  as  spoken  of  above,  will  sup- 
port a  bridge  comprising  the  entire  arch. 

It  should  be  remembered  that  the  preparation  of  the 
teeth  and  roots  for  the  support  of  a  bridge  is  the  same 
as  has  been  described  for  crown-work,  except  that  the 
trimming  of  the  sides  and    the  drilling    of  the   root- 


CROWN-    AND    BRIDGE-WORK. 


211 


canals  should  be,  as  far  as  possible,  in  parallel  lines,  so 
that  in  the  adjustment  of  the  finished  piece  the  crowns 
will  move  readily  to  their  place. 

The  simplest  and  no  doubt  the  most  practical  method 
of  bridge-work  is  that  first  described  by  Dr.  J.  L. 
Williams.  Two  or  three  typical  cases  will  be  described 
which  will  be  sufficient  to  present  the  subject. 

Fig.  121. 


Bridging  from  Cuspid  to  Cuspid.— Fig.  121 
shows  a  model  of  a  mouth  in  which  the  superior  laterals 
and  centrals  had  been  extracted.  The  canines  were 
badly  decayed,  with  exposure  of  the  pulp.  The  first 
step  is  the  removal  of  the  pulps  from  the  canine  roots. 
The  crowns  are  then  fitted  as  already  described  and 
placed  in  position.     An  impression  is  taken  in  plaster, 


212 


DENTAL    PROSTHESIS    AND    METALLURGY. 


the  crowns  remaining  embedded  on  its  removal.     The 
impression    is   varnished    and    oiled,   and  a  model   of 


Fig.  122. 


investing   material    poured.    After    this   has  hardened 
the  impression  is  carefully  cut  away,  and  we  have  a  model 


Fig.  123. 


of  the  mouth  with  the  crowns  in  position.    A  "  bite  "  is 
taken  and  the  articulation  secured  in  the  usual  manner. 


CROWN-    AND    BRIDGE-WORK. 


21 


The  remaining  crowns,  having  been  backed,  are  fitted, 
and  the  face  of  the  work  embedded  in  investing  mate- 
rial. 

The  whole  piece  is  now  united  at  the  back  by  solder- 
ing, and  when  finished  presents  the  appearance  shown 
at  Fig.  122. 

Fig.  124. 


Fig.  123  shows  a  model  of  the  mouth  after  the  bridge 
has  been  cemented  in  place. 

A  Lateral  Bridge. — Fig.  124  is  an  illustration  of 
a  piece  of  this  work  for  which  there  is  a  very  frequent 
demand.  It  is  for  supplying  the  loss  of  the  first  molar 
and  bicuspids.  If,  as  is  frequently  the  case,  there  is 
extensive  decay  in  the  cuspid,  it  will  be  best  to  excise 


214 


DENTAL   PROSTHESIS    AND    METALLURGY. 


the  remaining  portion  of  the  tooth  and  replace  an  arti- 
ficial crown  as  shown  in  the  illustration.  A  gold  cap 
is  then  made  for  the  second  molar.  If  this  tooth  is 
decayed  it  will  only  be  necessary  to  remove  the  decay, 
and  the  cement  which  is  used  for  setting  the  bridge 
will  make  the  most   perfect    filling    material    beneath 

Fig.  125. 


the  gold  cap.  The  intervening  molar  and  bicuspid 
crowns  are  made  in  the  following  manner :  the  porce- 
lain faces  are  backed  with  gold  or  platinum  and  the  tips 
ground  squarely  off.  Zinc  dies,  an  assortment  of  which 
should  be  made  from  the  grinding  surfaces  of  molars 
and  bicuspids,  or  the  die  plate  which  has  been  described 
in  another  place,  are  used  for  swaging  from  pure  gold  a 


CROWN-    AND    ERIDGE-WORK.  215 

tip  or  cusps  for  the  protection  of  the  porcelain  facing ; 
for  without  this  protection  the  porcelain  would  be  almost 
certain  to  be  broken.  The  concave  surface  of  these 
tips  is  filled  as  described  under  crown-work  with  solder 
of  a  little  lower  carat.  This  surface  is  then  ground 
smooth  and  fitted  to  the  squared  surface  of  the  porce- 
lain facing  and  waxed  in  position.  Triangular  pieces  of 
platinum  are  then  cut  of  the  proper  size  to  fit  the  sides 
of  the  tooth,  waxed  in  position,  and  the  whole  invested, 
leaving  the  back  open,  which  is  filled  with  coin-gold. 

These  teeth  are  then  fitted  into  position  in  the  bridge, 
as  previously  described. 

Fig.  125  shows  the  completed  work  in  the  mouth. 

Where  only  one  molar  or 
bicuspid    is     lost,    sufficient 
support  may  be  gained  by  the 
cap,  which  is  made  to    pass 
over  the  adjoining  molar.     If 
the  first  molar  and  second  bicuspid  are  lost,  the  anterior 
end  of  the  bridge  may  receive  sufficient  support  from  a 
strong  spur  (Fig.   126),  which  may  rest  in  a  cavity  in 
the  first  bicuspid,  and  around  which  a  filling  is  placed. 

Fig.  127  illustrates  a  device  for  obviating  the  neces- 
sity for  removing  the  crowns  of  natural  teeth  in  pre- 
paring the  mouth  for  bridge-work.  Crowns  are  fitted 
in  the  mouth  to  the  points  of  attachment  in  the  usual 
manner.  An  impression  is  taken,  bringing  the  crowns 
away  in  their  proper  positions.  From  this  the  cast  or 
model  is  obtained.  Heavy  bands  of  half-round  gold 
or  platinum  wire   are  now  fitted  around  the  necks  of 


2l6  DENTAL   PROSTHESIS   AND    METALLURGY. 

the   natural    teeth    on    their   lingual   surfaces.      These 

Fig.  127. 


Fig.   128. 


bands,  being  waxed  in  position,  serve  to  connect  the 
different  parts  of  the  bridge,  uniting  them  in  one  piece 


CROWN-    AND    BRIDGE-WORK. 


2 1 7 


without  the  loss  of  any  of  the  natural  crowns.     We  have 
found  this  a  highly  satisfactory  method  of  inserting  ex- 


Fig.  129. 


tensive  pieces  of  this  work.  Fig.  128  shows  the  mouth 
as  presented  for  which  the  bridge  was  constructed. 
Fig.  129  shows  the  piece  in  position. 


15 


DENTAL  METALLURGY. 


Metallurgy  may  be  defined  as  the  operation  of  ob- 
taining metals  from  their  ores,  their  physical  proper- 
ties or  special  characteristics,  and  the  methods  of  ma- 
nipulation. 

Physical  Properties  of  Metals. — The  physical 
aspects  of  metals  are  so  pronounced  that  they  form  a 
class  of  elements  by  themselves.  Some  of  the  most 
pronounced  characteristics  are  their  molecular  struc- 
ture, density,  malleability,  ductility,  tenacity,  tough- 
ness, hardness,  brittleness,  elasticity,  conductivity,  and 
fusibility. 

Molecular  Structure. — Like  all  other  elements, 
metals  are  composed  of  atoms  grouped  in  molecules, 
and  the  presence  of  any  other  element  or  extraneous 
force  altering  the  relation  of  the  atoms  in  the  molecules 
modifies  the  physical  properties  of  the  metal. 

Density. — The  density  of  a  metal  is  dependent  upon 
the  intimacy  of  the  contact  between  the  molecules. 
This  property  is  therefore  influenced  by  the  temperature 
of  casting,  the  rate  of  cooling,  the  mechanical  treat- 
ment, and  the  purity  of  the  metal. 

Malleability. — The  malleability   of  metals  is  the 

219 


2  20  DENTAL    PROSTHESIS    AND    METALLURGY. 

property  in  virtue  of  which  their  form  may  be  changed 
by  hammering  or  by  rolling. 

Ductility. — This  is  the  property  in  virtue  of  which 
metals  may  be  drawn  into  wire. 

Tenacity. — The  property  in  virtue  of  which  metals 
resist  attempts  to  pull  their  particles  asunder.  This 
embraces  adhesion  and  cohesion. 

Adhesion  is  the  force  which  unites  molecules  of 
different  kinds. 

Cohesion  is  the  force  which  unites  molecules  of  the 
same  kind. 

Toughness. — The  toughness  of  a  metal  is  the  prop- 
erty of  resisting  the  separation  of  their  molecules  after 
the  limit  of  elasticity  has  been  passed. 

Hardness. — By  this  term  we  refer  to  the  resist- 
ance offered  by  the  molecules  of  substances  to  their 
separation  by  the  penetrating  action  of  another  sub- 
stance. 

Brittleness. — The  property  in  virtue  of  which  the 
molecules  of  certain  bodies  are  easily  broken  apart. 

Elasticity. — The  power  certain  bodies  possess  of 
resuming  their  original  form  or  volume  size  after  the 
removal  of  an  external  force,  which  has  changed  that 
form  or  volume. 

Conductivity. — The  property  in  virtue  of  which 
metals,  to  a  greater  or  lesser  degree,  transmit  or  con- 
duct the  electric  current  or  the  impressions  of  heat  and 
cold. 

Fusibility. — The  property  in  virtue  of  which  metals 
upon   the  application   of  certain   degrees  of  heat  pass 


DENTAL   METALLURGY.  221 

from  a  solid  to  the  liquid  state.  On  account  of  the 
difficulty  experienced  in  determining  high  temperatures, 
only  those  that  fuse  or  melt  at  temperatures  below  2000 
F.  can  be  ascertained  with  absolute  accuracy.  Those 
above  this  point  must  be  taken  only  as  an  approxima- 
tion. 

Welding. — This  is  the  property  possessed  by  metals 
when  in  a  plastic  state  (the  stage  between  the  molten 
and  the  solid  state)  of  being  joined  together  by  the  co- 
hesion of  the  molecules,  induced  by  hammering. 

Atomic  Weight. — The  weight  of  an  atom  of  an 
element,  as  compared  with  the  weight  of  an  atom  of 
hydrogen. 

Alloys. — The  mechanical  properties  of  metals  are 
very  much  changed  by  associating  them  with  each  other 
in  the  form  of  an  alloy.*  They  are  usually  harder, 
more  brittle,  less  ductile  and  tenacious,  their  power  for 
conducting  heat  and  electricity  being  greatly  reduced. 
Their  fusing  point  is  usually  lowered,  that  is,  the  alloy 
melts  more  readily  than  that  of  the  least  fusible  constit- 
uent metal,  and  oftentimes  lower  than  that  of  any  of 
the  constituent  metals.  This  will  be  considered  more 
fully  in  another  place. 

In  the  following  chapters  the  metals  will  be  classified 
and  considered  according  to  their  usefulness  in  the 
dental  laboratory,     gold   being   the    first,   as  it    is    in 

*An  alloy  is  a  mixture  or  compound  of  two  or  more  metals, 
usually  formed  by  fusing  the  metals  together.  See  chapter  upon  the 
subject. 


222  DENTAL    PROSTHESIS    AND    METALLURGY. 

many  respects  the  chief  among  metals,  and  to  the  dental 
practitioner  of  the  greatest  importance. 


GOLD. 

Symbol,  Au  (Aurum).     Atomic  weight,  196. 2. 

Physical  Properties. — The  individuality  of  gold 
among  metals  is  strongly  marked,  owing  to  its  color, 
orange-red  or  yellow,  its  extreme  malleability  and  duc- 
tility (surpassing  all  other  metals),  its  perfect  resistance 
to  the  action  of  the  air  (non-oxidizable),  conducting 
power  for  heat  and  electricity,  high  fusing  point,  resist- 
ance to  simple  acids  (soluble  only  in  aqua  regia),  its 
rarity  and  consequent  intrinsic  value. 

The  fusing  point  of  gold  is  20160  F.  It  fuses 
with  considerable  expansion,  and  on  cooling  contracts 
more  than  any  other  metal. 

Properties  of  Particular  Alloys  of  Gold. — In 
the  dental  laboratory  gold  is  liable  to  become  contam- 
inated with  other  metals  which  are  highly  destructive  in 
their  influence  to  the  properties  which  adapt  gold  to 
the  various  needs  of  the  mechanical  operator.  Care 
should  be  taken  to  prevent  their  admixture  with  the 
gold  scraps  or  filings  that  are  to  be  reconverted  into  pro- 
per form  for  use.  The  effect  of  alloying  certain  metals 
with  gold  is  as  follows  : — 

Zinc  with  gold  forms  a  brittle  alloy,  and  when  com- 
bined in  equal  proportions  is  exceedingly  hard,  white, 
and  brittle. 


GOLD.  223 

Lead  renders  gold  intractable  (refractory  ;  not  easily 
managed). 

Tin,  bismuth,  and  arsenic  also  render  gold  in- 
tractable. 

Copper  hardens  and  toughens  gold  without  practi- 
cally impairing  its  malleability  ;  it  gives  a  deeper  color 
and  renders  it  capable  of  receiving  a  richer  polish. 

Silver  renders  gold  more  fusible,  increases  hardness, 
does  not  materially  affect  malleability,  and  gives  a 
lighter  color. 

Platinum  in  small  proportions  renders  gold  harder 
and  more  elastic  without  impairing  malleability.  Makes 
color  pale  and  dull.  Excess  of  platinum  renders  the 
alloy  infusible  in  the  blast  furnace. 

Mercury  dissolves  gold,  and  combines  with  it  at  all 
temperatures. 


PREPARING  ALLOYS  OF  GOLD  FOR  DENTAL 
PURPOSES. 

Gold  in  its  pure  state  is  rarely  employed  by  the 
dentist  in  laboratory  processes,  on  account  of  its  soft- 
ness and  flexibility ;  it  is,  therefore,  usually  alloyed  with 
such  metals  as  impart  to  it — without  practically  impair- 
ing its  malleability,  pliancy  or  purity — the  degree  of 
hardness,  strength,  and  elasticity  necessary  to  resist  the 
wear  and  strain  to  which  an  artificial  piece  constructed 
from  it  is  unavoidably  exposed  in  the  mouth. 

Reducing  Metals. — The  metals  with  which  gold  is 
usually  combined  are  copper  and  silver.     It  is  some- 


2  24  DENTAL    PROSTHESIS    AND    METALLURGY. 

times  reduced  with  silver  alone,  many  regarding  the 
introduction  of  copper  into  the  alloy  as  objectionable, 
as  plate  derived  from  it  is  supposed  to  be  more  readily 
tarnished  and  to  communicate  to  the  mouth  a  disagree- 
able metallic  taste.  The  small  proportion  of  copper 
usually  employed  in  forming  gold  plate,  however,  is 
not  likely  to  produce  in  any  objectionable  degree  the 
consequences  complained  of,  unless  the  fluids  of  the 
mouth  are  greatly  perverted.  If  gold  coin  is  used  in 
the  formation  of  plate,  it  may  be  sufficient  to  add  silver 
alone,  inasmuch  as  copper  is  already  present ;  though, 
usually,  additional  quantities  of  the  latter  metal  are 
added. 

Required  Fineness  of  Gold  Plate. — Alloys  of 
gold  to  be  permanently  worn  in  the  mouth  should  be  of 
such  purity  as  will  most  certainly,  under  all  the  con- 
tingencies of  health  and  disease,  resist  any  chemical 
changes  that  would  tend  to  compromise  either  the  com- 
fort or  health  of  the  patient.  It  should  not,  therefore, 
as  a  general  thing,  be  of  a  less  standard  of  fineness  than 
from  eighteen  to  twenty  carats.  It  may  exceed  this 
degree  of  purity  in  some  cases  (as  for  lower  dentures), 
but  will  rarely  or  never,  unless  alloyed  with  platinum, 
admit  of  being  used  of  a  higher  carat  than  the  present 
American  coin,  which  is  21.6  carats  fine. 

Formulas  for  Gold  Plate  used  as  a  Base  for 
Artificial  Dentures. — Any  of  the  following  formulas 
may  be  employed  in  the  formation  of  gold  plate  to  be 
used  as  a  base  or  support  for  artificial  dentures.  The 
relative  proportions  of  the  alloying  components   may 


GOLD.  225 

be  varied  to  suit  the  peculiar  views  or  necessities  of  the 
manipulator:  — 

GOLD    PLATE   EIGHTEEN   CARATS    FINE. 

Formula  No.  I.  Formula  No.  2. 

l8dwts.  pure  gold,  20  dvvts.  gold  coin, 

4  dwts.  fine  copper,  2  dwts.  fine  copper, 

2  dwts.  fine  silver.  2  dwts.  fine  silver. 

GOLD   PLATE   NINETEEN   CARATS    FINE. 

Formula  No.  3.  Formula  No.  4. 

19  dwts.  pure  gold,  20  dwts.  gold  coin, 

3  dwts.  copper,  25  grs.  copper, 
2  dwts.  silver.  40  -f-  grs.  silver. 

GOLD   PLATE   TWENTY   CARATS    FINE. 

Formula  No.  5.  Formula  No.  6. 

20  dwts.  pure  gold,  20  dwts.  gold  coin, 
2  dwts.  copper,  18  grs.  copper, 

2  dwts.  silver.  20  -\-  grs.  silver. 

GOLD    PLATE   TWENTY-TWO   CARATS    FINE. 
For  Crown-  and  Bridge-  Work. 

Formula  No.  7. 
22  dwts.  pure  gold, 

I  dwt.  fine  copper, 
18  grs.  silver, 

6  grs.  platinum. 

Formulas  for  Gold  Plate  used  for  Clasps, 
Wire  Backings,  etc. — Gold  used  in  the  formation  of 
clasps,  backings,  etc.,  is  improved  for  these  purposes  by 
the  addition  of  sufficient  platinum  to  render  it  firmer 
and  more  elastic  than  the  alloys  ordinarily  employed  in 


2  26  DENTAL    PROSTHESIS    AND    METALLURGY. 

the  formation  of  plate  as  a  base.  The  advantages  of 
this  elastic  property,  in  its  application  to  the  purposes 
under  consideration,  are,  that  clasps  formed  from  such 
alloys  will  adapt  themselves  more  accurately  to  the 
teeth,  as,  when  partially  spread  apart  on  being  forced 
over  the  crowns,  they  will  spring  together  again  and 
accurately  embrace  the  more  contracted  portions.  In 
the  form  of  stays  or  backings,  additional  strength  being 
imparted,  a  less  amount  of  substance  will  be  required  ; 
the  elasticity  of  these  supports,  also,  will  not  only  lessen 
the  chances  of  accident  to  the  teeth  themselves  in  mas- 
tication and  otherwise,  but  preserve  their  proper  posi- 
tion when  temporarily  disturbed  by  any  of"  the  forces 
applied  to  them. 

. 

Formula  No.  I.  Formula  No.  2. 

20  dwts.  pure  gold,  20  dwt.  coin  gold, 

2  dwts.  fine  copper,  8  grs.  fine  copper, 

1  dwt.  fine  silver,  10  grs.  silver, 

I  dwt.  platinum.  20  grs.  platinum. 

The  alloy  derived  from  either  of  these  formulas  will 
be  twenty  carats  fine. 

Gold  Solders. — Solders  are  a  class  of  alloys  by 
means  of  which  the  several  pieces  of  the  same  or  of 
different  metals  are  united  to  each  other.  They  should 
be  more  fusible  than  the  metals  to  be  united,  and  should 
consist  of  such  components  as  possess  a  strong  affinity 
for  the  substances  to  be  joined. 

Formula  No.  1  of  the  following  recipes  is  a  fraction 
over  fifteen  carats  fine ;  No.   2  furnishes  a  solder  eigh- 


GOLD.  227 

teen  carats  fine ;  and  No.  3  a  solder  twenty  carats  fine, 
for  crown-  and  bridge-work. 

Formula  No.  I.  Formula  No.  2. 

6  dwts.  gold  coin,  Gold  coin,  30'  parts. 

30  grs.  silver,  Silver,  4    " 

20  grs.  copper,  Copper  I     " 

10  grs.  brass.  Brass,  I     " 

Formula  No.  3. 
Pure  gold, 5  dwt- 

"    copper, 6  grs. 

"    silver, 12    " 

Spelter  solder, 6   " 

Method  of  Ascertaining  the  Carat  of  any 
given  Alloy.* — The  proportion  may  be  expressed  as 
follows : — 

"As  the  weight  of  the  alloyed  mass  is  to  the  weight 
of  gold  it  contains,  so  is  24  to  the  standard  sought. 
Take,  for  example,  Harris's  No.  3  gold  solder : — 

Pure  gold, 6  parts. 

"    silver, 2     " 

"    copper, 1     " 

<< 

Total, 9    " 

"The  total  proportion  would  be  expressed  thus:  — 

9  :  6  :  :  24  :  16. 

"  From  this  any  one  can  deduce  the  following  : — 
"  Rule. — Multiply  24  by  the  weight  of  gold  in  the 

*From  an  article  on  "  Alloying  of  Gold,"  by  Prof.  Watt. 


2  28  DENTAL   PROSTHESIS   AND    METALLURGY. 

alloyed  mass,  and  divide  the  product  by  the  weight  of 
the  mass  ;  the  quotient  is  the  carat  sought. 

"  In  the  above  example,  24  multiplied  by  6,  the  quan- 
tity of  gold,  gives  144,  which,  divided  by  9,  the  weight 
of  the  whole  mass,  gives  16.  Hence,  an  alloy  prepared 
as  above  is  16  carats  fine." 

To  Reduce  Gold  to  a  Required  Carat. — The 
proportion  may  be  expressed  as  follows : — 

"  As  the  required  carat  is  24,  so  is  the  weight  of  the 
gold  used  to  the  weight  of  the  alloyed  mass  when  re- 
duced. The  weight  of  gold  subtracted  from  this  gives 
the  quantity  of  alloy  to  be  added. 

"For  example,  reduce  6  ounces  of  pure  gold  to  16 
carats. 

"  The  statement  is  expressed  thus : — 

16  :   24  :  :   6  :  9. 

"  Six  subtracted  from  9  leaves  3,  which  is  the  quan- 
tity of  alloy  to  be  added.  From  this  is  deduced  the 
following :  — 

"  Rule. — Multiply  24  by  the  weight  of  pure  gold 
used,  and  divide  the  product  by  the  required  carat. 
The  quotient  is  the  weight  of  the  mass  when  reduced, 
from  which  subtract  the  weight  of  the  gold  used,  and 
the  remainder  is  the  weight  of  alloy  to  be  added." 

To  Raise  Gold  to  a  Higher  Carat. — This  may 
be  done  by  adding  pure  gold  or  a  gold  alloy  finer  than 
that  required.  The  principle  of  the  rule  may  be  set 
forth  in  the  following  general  expression:  — 

"  As  the  alloy  in  the  required  carat  is  to  the  alloy  in 


GOLD.  229 

the  given  carat,  so  is  the  weight  of  the  alloyed  gold 
used  to  the  weight  of  the  reduced  alloy  required.  The 
principle  may  be  practically  applied  by  the  follow- 
ing:— 

"  Rule. — Multiply  the  weight  of  the  alloyed  gold 
used  by  the  number  representing  the  proportion  of  alloy 
in  the  given  carat,  and  divide  the  product  by  that  re- 
presenting the  proportion  of  alloy  in  the  required  carat ; 
the  quotient  is  the  weight  of  the  mass  when  reduced  to 
the  required  carat  by  adding  fine  gold. 

"  To  illustrate  this,  take  the  following  example  :  — 

"Raise  1  pennyweight  of  16-carat  gold  to  18  carats. 

"  The  numbers  representing  the  proportions  of  alloy 
in  this  example  are  found  by  respectively  subtracting  18 
and  16  from  24.     The  statement  is,  therefore — 


from  which  it  follows  that  to  raise  1  pennyweight  of  16 
carat  gold  to  18  carats,  there  must  be  one-third  of  a 
pennyweight  of  pure  gold  added  to  it. 

"  But  suppose  that,  instead  of  pure  gold,  we  wish  to 
effect  the  change  by  adding  22-carat  gold.  The  num- 
bers, then,  respectively  representing  the  proportions  of 
the  alloy  would  be  found  by  subtracting,  in  the  above 
example,  16  and  18  from  22,  and  the  statement  would 

be— 

4  :  6  :  :  I  :  1%. 

"It  follows,  then,  that  to  each  pennyweight  of  16- 
carat  gold  a  half  pennyweight  of  22-carat  gold  must  be 
added  to  bring  it  to  18  carats." 


230  DENTAL    PROSTHESIS    AND    METALLURGY. 

REFINING  GOLD. 

Elements  Employed. — The  separation  of  foreign 
metals  from  gold  by  what  is  termed  the  "  dry  method  " 
is  effected  by  the  action  on  them  of  either  oxygen, 
chlorin,  or  sulphur,  converting  them  into  oxids,  chlorids, 
or  sulphurets.  Certain  compound  substances  are  used 
for  this  purpose  which,  when  heated  and  decomposed, 
yield  these  elements  in  sufficient  quantities  for  the  pur- 
poses specified.  The  refining  agents  in  common  use 
are  potassium  nitrate  (niter,  or  saltpeter),  which  yields 
oxygen  ;  mercuric  chlorid  (corrosive  sublimate),  which 
yields  chlorin ;  and  antimony  sulphid,  which  yields 
sulphur. 

Separation  of  Foreign  Metals  from  Gold. — The 
most  troublesome  ingredients  which  find  their  way  into 
gold  alloys  are  what  are  commonly  called  base  metals, 
as  tin,  lead,  zinc,  iron,  antimony,  bismuth,  etc.  In 
attempting  to  separate  these  metals  from  gold,  it  is  not 
a  matter  of  indifference  what  reagent  is  employed,  in- 
asmuch as  distinct  affinities  exist,  which  may  be  advan- 
tageously consulted.  If,  for  example,  zinc  or  iron  or 
both  of  these  metals  are  present  in  small  quantities,  any 
compound  which  yields  oxygen  will,  by  virtue  of  the 
affinity  of  the  latter  for  these  metals,  effect  their  separa- 
tion by  converting  them  into  oxids  ;  hence,  when  these 
metals  are  to  be  got  rid  of,  potassium  nitrate  is  em- 
ployed. But  oxygen  has  a  feeble  affinity  for  tin,  and 
when  this  metal  is  present,  its  separation  is  better  effected 
by  some  compound  which  parts  with  chlorin  in  the  act 


gold.  23 r 

of  decomposition ;  mercuric  chlorid  is  therefore  used 
for  the  purpose.  When  the  alloy  of  gold  contains  a 
number  of  these  metals  at  the  same  time,  and  is  very 
coarse,  antimony  sulphid,  which  is  a  very  powerful  and 
efficient  reagent,  should  be  resorted  to,  unless  the 
operator  should  prefer,  and  which  is  the  better  way,  to 
reduce  the  alloy  to  pure  gold  by  the  "  humid  method." 

The  Dry  Method. — After  all  traces  of  iron  or  steel 
have  been  removed  from  the  gold  fragments  and  filings 
by  passing  a  magnet  repeatedly  through  them,  the  latter 
should  be  placed  in  a  clean  crucible,  lined  on  the  inside 
with  borax,  and  covered  either  with  a  piece  of  fire-clay 
slab  or  broken  crucible.  Sheet-iron  has  been  recom- 
mended for  the  latter  purpose,  but  should  never  be  used, 
as,  when  highly  heated,  scales  form  on  the  surface,  and 
are  liable  to  drop  in  upon  the  fused  metals.  If  the  opera- 
tion is  likely  to  be  protracted,  an  inverted  crucible,  with 
a  hole  in  the  bottom,  may  be  securely  luted  to  the  top 
of  the  one  containing  the  metals,  the  refining  agents 
and  fluxes  being  introduced  through  the  opening  in  the 
upper  crucible.  These  are  then  placed  in  the  furnace, 
on  a  bed  of  charcoal,  or,  what  is  better,  a  mixture  of 
charcoal  and  coke,  the  latter  being  built  up  around  the 
crucible,  and  over  it  when  covered  with  a  second  cruc- 
ible, care  being  taken  that  no  fragments  of  fuel  are  per- 
mitted to  fall  in  upon  the  fused  metals.  The  process  is 
as  follows : — 

First  melt  the  alloy  at  a  high  temperature, 
to  oxidize  the  base  metals ;  the  refining  agents  may 
then   be  added  in  small  quantities  from  time  to  time, 


232  DENTAL    PROSTHESIS    AND    METALLURGY. 

and  the  heat  continued  from  half  an  hour  to  an  hour, 
according  to  the  coarseness  of  the  alloy.  The  agents 
first  employed  are  borax  and  potassium  nitrate  (KN03). 
The  latter  assists  the  oxidation  by  parting  with  its 
oxygen,  when  the  foreign  metals  will  generally  become 
entirely  oxidized  and  dissolved  in  the  slag. 

The  crucible  should  be  removed  from  the  fire,  and 
the  metals  allowed  to  cool  gradually.  The  crucible 
may  now  be  broken  and  the  button  of  gold  at  the 
bottom  removed  and  separated  from  the  slag  that  covers 
it  with  a  hammer.  The  gold  should  then  be  put  into  a 
fresh  crucible  and  remelted  for  pouring  into  ingot- 
molds,  which  should  be  previously  warmed  and  oiled. 
This  treatment,  with  nitrate  of  potassa  and  borax,  will 
usually  be  sufficient,  as  most  metals  are  oxidizable.  If, 
however,  after  hammering,  annealing,  and  rolling  the 
ingot,  it  should  still  be  found  brittle,  it  must  be  re- 
melted,  and  some  other  refining  agent  employed  to 
remove  the  traces  of  the  base  metals.  If  it  is  known 
what  foreign  metal  is  present,  the  particular  reagent 
which  will  most  readily  attack  it  should  be  used.  But 
if,  as  is  often  the  case,  the  alloy  is  of  uncertain  com- 
position, or  contains  several  metals  having  distinct 
affinities,  the  process  becomes  to  some  extent  experi- 
mental, making  it  necessary  to  use  first  one  refining 
agent  and  then  another,  until,  from  the  appearance  and 
the  manipulation  of  the  gold,  it  is  found  to  be  free  from 
alloy.     The  special  reagents  employed  are  as  follows  : — 

When  tin  or  lead  is  present,  add  mercuric  chlo- 
rid,    HgCl2   (corrosive   sublimate),    and   zinc    chlorid, 


GOLD.  233 

ZnCl4,  or  lead  chlorid,  PbCl2,  are  formed  and  with  the 
mercury  volatilized  by  the  heat. 

When  silver  is  present,  add  to  the  molten  alloy 
from  two  to  four  times  its  weight  of  antimony  sulphid, 
Sb2S3;  this  must  be  added  carefully  and  a  little  at  a 
time.  The  heat  decomposes  the  sulphids.  The  sulphur 
unites  with  the  silver  and  other  base  metals,  forming 
sulphids,  while  the  antimony  unites  with  the  gold,  form- 
ing a  leaden-colored  alloy.  When  effervescence  has 
ceased,  remove  the  crucible  from  the  fire  and  allow  it 
to  cool.  The  antimony  and  gold  alloy  will  be  found  in 
the  bottom  of  the  crucible,  and  the  sulphids  on  the 
surface. 

To  separate  the  antimony  from  the  gold,  remelt 
the  alloy  and  throw  upon  the  molten  mass  a  current  of 
air  from  a  blowpipe.  Antimony  oxid,  Sb203,  is  formed 
and  volatilized  ;  continue  the  process  until  fumes  cease 
to  be  given  off. 

When  Iridium  is  Present. — Prof.  Essig,  in  writing 
upon  the  subject,  says:  "  The  little,  hard  grains  occa- 
sionally met  with  in  gold,  upon  which  the  file  makes  no 
impression,  consist  of  iridium,  or  a  native  alloy  of  osmium 
and  iridium,  and  are  not  combined  with  the  gold,  but 
merely  disseminated  through  it.  The  only  dry  method 
of  separating  it  from  gold  consists  in  alloying  the  latter 
with  three  times  its  weight  in  silver,  by  which  means  the 
specific  gravity  of  the  metal  is  so  much  lowered  that 
iridium,  which  is  very  infusible  and  of  a  specific  gravity 
of  21. 1,  will  subside  to  the  bottom  of  the  crucible, 
when  the  gold  and  silver  alloy  may  be  poured  or  ladled 
16 


234  DENTAL    PROSTHESIS    AND    METALLURGY. 

off.  As  some  of  the  gold  will  remain  with  the  residue, 
more  silver  must  be  melted  with  it,  the  operation  being 
repeated  several  times  until  nearly  all  the  gold  is  re- 
moved." The  gold  and  silver  alloy  may  then  be  sepa- 
rated as  directed  above. 

When  Platinum  is  Present. — If,  after  treating 
the  alloy  with  the  reagents  enumerated,  it  should  be 
found  malleable,  but  stiff  or  elastic  and  of  a  rather  dull 
color,  it  is  due  to  the  presence  of  platinum,  and  any 
further  attempts  to  reduce  it  by  the  "dry  process"  will 
prove  unavailing.  It  must  then  be  subjected  to  what 
will  hereafter  be  described  as  the  "humid,  or  wet 
method." 

The  Humid  Method. — When  it  is  desired  to  re- 
duce the  alloy  to  pure  gold,  which  is  generally  advisable 
whenever  the  gold  to  be  refined  consists  of  very  coarse 
filings,  fragments  of  plate  containing  large  quantities  of 
solder,  linings  with  platinum  pins  attached,  particles  of 
base  metals,  etc.,  the  "humid,  or  wet  method,"  as  it  is 
called,  should  be  employed.  The  solvents  in  common 
use  for  this  purpose  are  nitric,  sulphuric,  and  nitro-muri- 
atic  or  hydrochloric  acid ;  but  as  the  desired  results  can 
be  more  conveniently  and  directly  obtained  by  the  use 
of  the  latter,  or  hydrochloric  acid,  this  most  available 
method  alone  will  be  given.  The  following  practical 
remarks  on  the  subject  are  from  an  article  on  the  "  Man- 
agement of  Gold,"  by  Professor  George  Watt : — 

"When  the  alloy  is  composed  of  metals  differing  but 
little  in  their  affinities  for  oxygen,  chlorin,  etc.,  we  resort 
to  one  of  the  '  wet  methods.'    And,  in  this  connection, 


GOLD.  235 

we  will  only  describe  the  one  which  we  consider  the  most 
convenient  and  effectual  for  the  practical  dentist.  It  is 
effectual  in  all  cases,  as  it  always  gives  us  pure  gold. 

"Let  us,  then,  suppose  that  our  gold  alloy  has  be- 
come contaminated  with  platinum  to  such  an  extent  that 
the  color  and  elasticity  of  the  plate  are  objectionable. 
The  alloy  should  be  dissolved  in  nitro-muriatic  or 
hydrochloric  acid,  called  aqua  regia.  The  best  pro- 
portions for  aqua  regia  are  three  parts  of  hydrochloric 
acid  to  one  of  nitric.  If  the  acids  are  at  all  good, 
four  ounces  of  the  aqua  regia  will  be  an  abundance 
for  an  ounce  of  the  alloy.  The  advantage  of  using  the 
acids  in  the  proportion  of  three  to  one,  instead  of  two 
to  one,  as  directed  in  most  of  the  text-books,  is,  that 
when  the  solution  is  completed  there  is  but  little,  if  any, 
excess  of  nitric  acid.  If  the  acids  be  '  chemically 
pure,'  four  parts  of  the  hydrochloric  to  one  of  the 
nitric  produces  still  better  results. 

"By  this  process  the  metals  are  all  converted  into 
chlorids;  and,  as  the  chlorid  of  silver  is  insoluble,  and 
has  a  greater  specific  gravity  than  the  liquid,  it  is  found 
as  a  grayish-white  powder  at  the  bottom  of  the  vessel. 
The  chlorids  of  the  other  metals,  being  soluble,  remain 
in  solution.  By  washing  and  pouring  off,  allowing  the 
chlorid  of  silver  time  to  settle  to  the  bottom,  the  solu- 
tion may  be  entirely  separated  from  it. 

"  The  object  is  now  to  precipitate  the  gold  while 
the  others  remain  in  solution.  This  precipitation  may 
be  effected  by  any  one  of  several  different  agents,  but 
we  will  mention  only  the  protosulphate  of  iron. 


236  DENTAL   PROSTHESIS   AND    METALLURGY. 

''This  salt  is  the  common  green  copperas  of  the 
shops,  and,  as  it  is  always  cheap  and  readily  obtained, 
we  need  look  no  further.  It  should  be  dissolved  in 
clean  rain-water,  and  the  solution  should  be  filtered, 
and  allowed  to  settle  until  perfectly  clear.  Then  it  is 
to  be  added  gradually  to  the  gold  solution  as  long  as  a 
precipitate  is  formed,  and  even  longer,  as  an  excess 
will  the  better  insure  the  precipitation  of  all  the  gold. 
The  gold  thus  precipitated  is  a  brown  powder,  having 
none  of  the  appearances  of  gold  in  its  ordinary 
state.  The  solution  should  now  be  filtered,  or  the 
gold  should  be  allowed  to  settle  to  the  bottom, 
where  it  may  be  washed  after  pouring  off  the  solution. 
It  is  better  to  filter  than  decant  in  this  case,  as,  fre- 
quently, particles  of  the  gold  float  on  the  surface,  and 
would  be  lost  in  the  washings  by  the  latter  process. 

"  Minute  traces  of  iron  may  adhere  to  the  gold  thus 
precipitated.  These  can  be  removed  by  digesting  the 
gold  in  dilute  sulphuric  acid  ;  and,  when  the  process  is 
properly  conducted  thus  far,  the  result  is  pure  gold, 
which  may  be  melted,  under  carbonate  of  potash,  in  a 
crucible  lined  with  borax,  and  reduced  to  the  required 
carat." 

PLATINUM. 

Symbol,  Pt.     Atomic  weight,  1 97. 

General  Properties. — Platinum  is  a  grayish-white 
metal,  resembling,  in  some  measure,  polished  steel.  It 
is  harder  than  silver,  and  has  a  density  greater  than  any 


PLATINUM.  237 

known  metal,  its  specific  gravity  being  21.25.  A  white 
heat  does  not  tarnish  it,  nor  is  it  in  any  way  affected 
by  exposure,  either  in  the  air  or  water.  It  is  insoluble 
in  any  of  the  simple  acids,  niiro- muriatic  acid  (aqua 
regia)  being  the  only  one  that  dissolves  it.  It  expands 
less  by  heat  than  any  other  metal,  and  is  much  inferior 
to  gold,  silver,  and  copper  as  a  conductor  of  electricity. 

Platinum  is  soft  and  flexible,  and  when  rolled  into 
thin  sheets,  say  28  or  30  of  the  gauge-plate,  and  well- 
annealed  at  a  strong  white  heat  for  eight  or  ten  minutes, 
it  may  be  readily  forced  into  all  the  inequalities  of  a 
zinc  die  without  producing  any  appreciable  change  in 
the  face  of  the  latter. 

The  Fusing  Point  of  platinum  is  above  35000 
Fahrenheit,  to  reach  which,  in  the  laboratory,  it  is 
necessary  to  employ  the  oxy-hydrogen  blow-pipe. 

Use  for  Dental  Purposes. — Platinum,  in  me- 
chanical practice,  is  chiefly  employed  as  a  base  for  con- 
tinuous-gum work ;  as  a  coloring  ingredient  of  porce- 
lain ;  for  pins  for  attaching  mineral  teeth  ;  for  backings, 
and  dowels  in  crown-  and  bridge-work ;  and,  to  a 
limited  extent,  in  some  of  the  minor  operations  of  the 
laboratory. 

Solder  for  Platinum. — Pure  gold  is  the  only  pro- 
per solder  for  this  metal. 

Alloys  of  Platinum. — Platinum  unites  with  most 
of  the  base  metals,  forming  alloys  of  variable  degrees 
of  hardness,  elasticity,  brittleness,  color,  fusibility,  etc., 
but  their  practical  value  to  the  dentist  is  not  sufficient 
to  justify  a  separate  description  of  their  properties. 


238  DENTAL    PROSTHESIS    AND    METALLURGY. 

With  gold,  it  forms  a  straw-colored  alloy,  the  shade 
depending  on  the  quantity  of  gold  added.  Silver  hard- 
ens it,  the  resulting  alloy  being  unaffected  by  sulphur. 

Platinoid  Metals. — The  platinoid  metals,  palla- 
dium, iridium,  osmium,  rhodium,  and  ruthenium,  are 
native  contaminations,  the  alloys  of  these  metals  hav- 
ing a  close  general  resemblance  to  platinum. 

Among  the  platinoid  metals,  palladium  and  iridium 
are  the  only  ones  that  have  been  used  for  dental  pur- 
poses, and  these  only  to  a  limited  extent. 

Palladium  is  of  a  steel-gray  color,  and  when  plan- 
ished, is  a  brilliant,  steel-white  metal,  not  liable  to 
tarnish  in  the  air.  Though  closely  resembling  platinum, 
it  may  be  readily  distinguished  from  the  latter  metal 
by  the  following  tests :  1.  It  has  little  more  than  one-half 
the  density  of  platinum.  2.  If  a  piece  of  it  is  heated 
to  redness,  it  assumes  a  bronze-blue  shade,  of  greater 
or  less  intensity,  as  it  is  cooled  more  or  less  slowly  ; 
but  if  it  is  suddenly  chilled  by  immersing  it  in  cold 
water,  it  instantly  resumes  its  original  luster.  3.  When 
a  drop  of  the  tincture  of  iodin  is  let  fall  upon  its  sur- 
face and  evaporated  over  the  flame  of  a  lamp,  a  black 
spot  remains,  which  does  not  occur  with  platinum. 
Palladium  melts  at  about  the  heat  required  to  fuse 
malleable  iron,  and  is  the  most  fusible  of  the  plantinoid 
metals.  It  is  soluble  in  nitric  acid,  but  its  best  solvent 
is  nitro-hydrochloric  acid. 

Palladium,  being  very  costly,  and  possessing  no 
properties  that  specially  recommend  it  for  dental  use,  is 
but  little  employed  in  prosthetic  practice. 


SILVER.  239 

Iridium,  though  generally  found  associated  with 
platinum,  osmium,  and  other  allied  metals,  sometimes 
occurs  native  and  nearly  pure.  It  is  very  refractory 
when  exposed  to  high  temperatures,  and  can  only  be 
fused  by  the  oxy-hydrogen  blowpipe  or  by  the  heat  of 
the  voltaic  current. 

The  extreme  hardness  and  consequent  rigidity  of 
iridium  renders  it  in  its  unalloyed  state  practically 
unfit  for  base  plates,  on  account  of  the  great  difficulty 
of  swaging  it  into  proper  form. 


SILVER. 

Symbol,  Ag  (Argentum).      Atomic  weight,  108. 

General  Properties  of  Silver. — Pure  silver,  when 
planished,  is  the  brightest  of  the  metals.  It  is  remark- 
ably laminable  and  ductile.  It  exceeds  gold  in  tenacity 
or  cohesion,  but  is  inferior  to  platinum  in  this  respect. 
Fine  silver  is  unaffected  by  moisture  or  pure  atmospheric 
air,  but  is  readily  tarnished  with  a  film  of  brown  sul- 
phuret  by  exposure  to  sulphuretted  hydrogen.  The 
sulphuret  of  silver  thus  formed  may  be  easily  removed 
by  rubbing  the  metal  with  a  solution  of  chameleon  min- 
eral, prepared  by  calcining  equal  parts  of  black  or 
peroxid  of  manganese  and  niter.  Unlike  gold  and  plati- 
num, it  is  readily  soluble  in  nitric  acid,  this  and  sulphuric 
acid  being  the  only  simple  ones  that  dissolve  it. 

Fusing  Point. — Silver  fuses  at  an  extreme  red  heat, 
generally  estimated  at  18730  F.     It  becomes  very  bril- 


240  DENTAL    PROSTHESIS    AND    METALLURGY. 

liant  when  heated ;  boils  and  vaporizes  above  its  fusing 
point ;  and  when  cooled  slowly  its  surface  presents  a 
crystalline  appearance. 

Alloys  of  Silver. — Silver  combines  readily  with 
most  metals,  forming  compounds  of  variable  degrees  of 
malleability,  ductility,  density,  etc. 

Tin,  zinc,  antimony,  lead,  bismuth,  and  arsenic  ren- 
der it  brittle.  A  very  minute  quantity  of  tin  is  fatal  to 
the  ductility  of  silver.  Silver  does  not  easily  combine 
with  iron,  although  the  two  metals  may  be  united  by 
fusion.  Gold,  copper,  platinum,  iridium,  steel,  man- 
ganese, and  mercury  also  form  alloys  with  silver. 

Refining  Alloys  of  Silver. — The  following  ac- 
counts of  the  manner  of  obtaining  pure,  or  nearly  pure, 
silver  from  alloys  of  that  metal  by  the  dry,  and  wet,  or 
humid,  methods  are  given  by  Prof.  Essig  in  his  treatise 
on  "Dental  Metallurgy  •  " — 

Dry  Method. — "  The  dry  method,  or  assaying  pro- 
cess, consists  in  forming  an  alloy  of  the  silver  with  lead, 
and  is  especially  applicable  to  ores  and  the  sweepings 
of  the  dentist's  laboratory.  The  specimen  to  be  treated 
is  heated  with  from  twelve  to  thirty  times  its  weight  of 
granulated  lead,  in  a  bone-ash  cupel,  which  is  placed  in 
a  muffle  so  arranged  that  a  current  of  atmospheric  air 
may  pass  freely  over  the  vessel  and  oxidize  the  lead. 
This  oxid  of  lead,  being  quite  fusible,  combines  with 
any  base  metal  present  and  oxidizes  it,  uniting  subse- 
quently with  the  oxid  as  a  fusible  slag,  while  the  gold 
or  silver  will  be  held  by  the  unoxidized  portion  of  the 
lead.     In  the  treatment  of  specimens  of  alloy,  such  as 


SILVER.  24I 

plate  or  coins,  a  quantity  of  the  specimen  is  accurately 
weighed  and  mixed  with  from  four  to  five  times  its 
weight  of  pure  granulated  lead.  It  is  then  placed  in 
the  cupel  and  exposed  to  heat,  as  above  described,  un- 
til all  the  lead  is  oxidized  or  converted  into  litharge, 
when  the  remaining  button  assumes  the  brilliant  appear- 
ance of  surface  to  which  allusion  has  been  previously 
made,  denoting  that  the  base  metals  or  oxidizable  con- 
stituents have  been  oxidized  and  taken  up  by  the  lead 
oxid.  This  button  is  then  to  be  weighed  by  means  of 
a  delicate  assay  balance,  and  the  loss  of  weight  denotes 
the  amount  of  alloy  that  was  present. 

Wet  Method. — "  Pure  silver,  which  is  reckoned  as 
1000  fine,  may  be  obtained  from  standard  or  other 
grades  of  silver  by  dissolving  them  in  nitric  acid  slightly 
diluted  with  water,  the  solution  being  much  facilitated 
by  exposure  to  gentle  heat.  If  gold  be  associated  with 
the  alloy  it  will  be  found  at  the  bottom  of  the  vessel, 
in  which  case  it  will  be  necessary  to  use  a  siphon  to  re- 
move the  argentic  nitrate  solution.  The  silver  is  now 
to  be  precipitated  in  the  form  of  chlorid  by  the  addition 
of  an  excess  of  common  salt.  When  all  has  subsided 
the  liquid  is  carefully  poured  off,  and  the  chlorid  thor- 
oughly washed,  to  remove  all  traces  of  acid.  The 
chlorid  is  then  placed  in  water  acidulated  with  hydro- 
chloric acid  (an  ounce  of  chlorid  requiring  six  to  eight 
ounces  of  water)  and  pieces  of  clean  wrought-iron  put 
in  it,  when  a  copious  evolution  of  hydrogen  follows, 
which,  uniting  with  the  chlorin  of  the  argentic  chlorid, 
liberates  metallic  silver.     The  latter  should  not  be  dis- 


242  DENTAL    PROSTHESIS    AND    METALLURGY. 

turbed  until  the  last  particle  of  it  is  thus  reduced,  when 
it  will  be  found  to  be  a  spongy  mass.  The  undissolved 
iron  should  now  be  carefully  removed,  the  ferrous  and 
ferric  chlorid  carefully  decanted,  and  the  silver  washed 
in  hot  water  containing  about  one-tenth  its  bulk  of 
hydrochloric  acid.  This  is  repeated  several  times,  and 
finally  the  silver  is  again  thoroughly  washed  with  pure 
hot  water.  The  silver,  after  drying,  is  then  ready  for 
melting,  and  if  care  has  been  observed  in  the  process  it 
will  be  found  to  be  of  a  fineness  of  999.7  parts  in  1000, 
the  0.3  of  impurity  present  being  due  to  traces  of  iron. 
The  chlorids  may  be  acidulated  with  sulphuric  acid, 
and  reduced  with  zinc  instead  of  iron." 

Reduction  of  Silver  to  the  Required  Forms 
for  Dental  Purposes. — Owing  to  the  very  soft  and 
flexible  nature  of  silver  in  its  pure  state,  it  is  usual, 
when  converting  it  into  plate  or  other  forms  for  use,  to 
employ  an  alloy  of  the  metal.  Hence  silver  coins, 
which  are  made  harder  by  the  copper  they  contain,  are 
generally  selected  for  the  purpose.  The  tendency  of 
silver  to  tarnish  in  the  mouth  when  alloyed  with  copper 
may  be  diminished  by  boiling  the  finished  piece  in  a 
solution  of  cream  of  tartar  and  chlorid  of  soda,  or 
common  salt,  or  by  scrubbing  it  with  aqua  ammonia, 
which  removes  the  superficial  particles  of  copper  and 
exposes  a  surface  of  fine  silver.  When  platinum  is 
introduced  as  the  sole  alloying  component,  the  purity 
of  the  silver  is  not  only  preserved,  but  the  alloy  is  less 
easily  acted  on  chemically. 

Formulas  for  Silver  Solders. — Silver  solders  are 


ALUMINUM.  243 

usually  composed  of  silver,  copper,  and  zinc  in  variable 
proportions.  Alloys  formed  from  the  following  form- 
ulas are  such  as  are  generally  employed  in  soldering 
silver  plate  derived  from  the  coins  of  that  metal. 
Three-cent  pieces,  composed  of  two  parts  silver  and 
one  of  copper,  may  be  used  for  the  same  purpose  : — 

Formtila  No.  1.  Formula  No.  2. 

Silver,     ...  66  parts.  Silver,      ...  6  parts. 

Copper,   ...  30     "  Copper,    ...  2      " 

Zinc,    ....  10     "  Brass,  .    .    .    .  1  part. 

In  compounding  silver  solders,  the  silver  and  copper 
should  be  first  melted,  and  the  zinc  or  brass  afterward 
added,  when  they  should  be  quickly  poured,  to  prevent 
undue  waste  by  oxidation  of  the  more  fusible  compo- 
nent. The  ingot,  when  cold,  should  be  rolled  into  a 
plate  a  little  thicker  than  that  recommended  for  gold 
solder. 


ALUMINUM. 

Symbol,  Al.     Atomic  tveight,  27. 

Derivation. — Aluminum  is  the  metallic  basis  of 
alumina,  the  latter  being  the  characteristic  ingredient 
of  common  clay.  It  is  only  within  a  comparatively 
few  years  that  the  attention  of  chemists  has  been 
directed  to  the  production  of  this  metal,  with  a  view 
to  its  general  introduction  into  commerce  and  the  arts. 
The  improvements  in  the  methods  of  obtaining  it, 
which    have     been    more    recently    introduced,    have 


2  44  DENTAL    PROSTHESIS    AND    METALLURGY. 

rendered  its  production  economical,  and  it  is  now 
supplied  in  large  quantities  and  in  a  greatly  improved 
condition. 

General  Properties. — One  of  the  most  striking 
properties  of  aluminum  is  its  extreme  lightness,  it  being 
the  lightest  of  commercial  metals,  having  a  specific 
gravity  of  2.6,  whilst  that  of  platinum  is  21.5  and  gold 
19.5.  It  is  very  malleable  and  ductile,  and  can  be  re- 
duced to  thin  sheets  or  drawn  into  very  fine  threads. 
Its  tenacity,  though  superior  to  that  of  silver,  is  less 
than  that  of  copper,  but  no  very  accurate  experiments 
have  been  made  in  this  respect. 

When  pure  it  is  about  as  hard  as  silver,  is  readily 
manipulated,  and  is  capable  of  taking  and  retaining  a 
very  high  polish. 

Fusing  Point. — Aluminum  melts  at  a  temperature 
between  silver  and  zinc,  or  about  11600  F.  (according 
to  the  latest  experiments).  When  casting  aluminum  it 
should  not  be  heated  much  above  the  fusing  point,  or  be 
allowed  to  remain  melted  for  any  great  length  of  time. 

Corrodibility. — One  of  the  most  marked  qualities 
of  aluminum  is  its  resistance  to  oxidation,  from  the 
influence  of  the  air.  As  now  manufactured,  this  metal 
is  also  found  to  withstand  the  action  of  organic  secre- 
tions fully  as  well  as  silver,  and  is  receiving  a  much 
larger  use  as  a  base  for  dental  plates. 

Solubility. — The  natural  solvent  for  aluminum  is 
hydrochloric  acid.  Concentrated  sulphuric  acid  also 
dissolves  aluminum,  while  nitric  acid,  either  concen- 
trated or  diluted,  has  very  little  action  upon  it. 


ALUMINUM.  245 

Electrical  Conductivity. — Pure  aluminum  has  an 
electrical  conductivity  of  about  one-half  that  possessed 
by  silver  or  copper,  and  about  two-thirds  that  of  gold. 

Manner  of  Annealing. — For  the  purpose  of  an- 
nealing aluminum  the  surface  of  the  plate  may  be  coated 
with  oil,  and  then  passed  over  the  flame  of  a  spirit 
lamp  or  Bunsen  burner  until  the  oil  is  entirely  burned 
oif  and  the  plate  becomes  white,  when  it  is  instantly 
withdrawn.  Or  it  may  be  accomplished  by  placing  the 
piece  of  plate  in  a  furnace  muffle,  an  even  heat  being 
maintained  until  the  metal  is  hot  enough  to  char  the  end 
of  a  pine  stick,  which  should  leave  a  black  mark  behind 
it  as  it  is  drawn  over  the  plate.  The  metal  on  being 
withdrawn  should  be  allowed  to  cool  slowly. 

Melting. — Aluminum  should  be  melted  in  ordinary 
plumbago  crucibles.  The  metal  does  not  absorb  or  unite 
with  carbon  when  heating  in  contact  with  it.  No  flux  is 
needed  to  cover  the  molten  metal,  as  it  is  non-volatile  at 
any  temperature  that  can  be  obtained  with  an  ordinary 
furnace. 

Casting. — Aluminum  is  now  being  used  to  consider- 
able extent  in  castings  of  all  descriptions  where  light- 
ness, non-corrodibility,  and  silvery  color  is  desired. 
Either  iron,  sand,  or  plaster  and  marble  dust  molds 
can  be  used,  the  metal  being  poured  as  cold  as  pos- 
sible. 

Polishing. — The  truly  distinctive  and  beautiful 
color  of  aluminum  is  best  brought  out  in  highly  polished 
plate.  To  polish,  use  rouge  or  tripoli ;  or  "Almeta 
Polish,"   which  was  introduced  by  the  Pittsburgh  Re- 


246  DENTAL    PROSTHESIS    AND    METALLURGY. 

duction  Co.,  has  earned  a  well-merited  reputation  as 
an  aluminum  polish.     Its  formula  is  as  follows  : — 

Stearic  Acid, one  part, 

Fuller's  Earth, one  part, 

Rotten  Stone, .six  parts. 

The  whole  ground  very  fine  and  well  mixed. 

Soldering. — Several  methods  of  soldering  aluminum 
have  proven  more  or  less  successful  for  some  purposes ; 
none  of  them,  however,  are  suitable  for  attaching 
artificial  teeth  to  be  worn  in  the  mouth.  The  only  way 
in  which  the  metal  has  been  successfully  employed  as  a 
dental  base  is  with  the  rubber  attachment. 

Alloys. — Aluminum,  like  iron,  does  not  unite  with 
mercury,  and  scarcely  at  all  with  lead.  It,  however, 
forms  a  variety  of  alloys  with  other  metals.  It  seems 
to  unite  readily  with  zinc,  and  these  have  been  found  to 
give  the  best  promise  as  solders  for  aluminum  ;  but,  un- 
fortunately, when  melted,  neither  of  them  are  sufficiently 
liquid  and  do  not  run  readily.  A  variety  of  alloys  with 
nickel  have  been  made,  and  that  consisting  of  100  parts 
of  aluminum  and  3  of  nickel  is  found  to  work  readily, 
and  to  have  gained  hardness  and  rigidity  as  compared 
with  the  pure  metal.  The  alloys,  however,  with  copper 
are  the  most  striking  ;  they  are  light  and  very  hard,  and 
capable  of  a  fine  polish.  In  the  same  degree  that 
copper  adds  to  the  hardness  of  aluminum,  so  does  the 
latter,  when  used  in  small  quantities,  give  hardness  to 
copper  without  injuring  its  malleability. 


ZINC — LEAD.  247 

ZINC. 

Symbol,  Zn  (Zincum).     Atomic  weight,  65. 

General  Properties. — Zinc  is  a  bluish-white  metal, 
the  fresh  surface  possessing  considerable  luster.  It  does 
not  easily  tarnish  in  dry  air,  but  soon  becomes  dull  on 
exposure  to  moisture.  Under  ordinary  circumstances 
it  is  brittle,  but  when  heated  to  about  3000  F.  it  be- 
comes malleable  and  ductile. 

The  fusing  point  of  zinc  is  about  7750  F.,  and 
when  heated  to  about  18000  F.  it  boils,  volatilizes,  and 
burns,  if  the  air  is  not  excluded,  with  a  brilliant,  green- 
ish-white flame,  the  oxid  being  formed. 

Use  for  Dental  Purposes. — Zinc  has  been  long 
employed  in  the  formation  of  dies  used  in  swaging 
metallic  plates,  this  being  its  principal  use  in  the  dental 
laboratory. 

LEAD. 

Symbol,  Pb  (Plumbum).     Atomic  weight,  206.5. 

General  Properties. — Lead  has  a  grayish-blue 
color,  with  a  bright,  metallic  luster  when  melted  or  newly 
cut,  but  it  soon  becomes  tarnished  when  exposed  to  the 
air.  It  is  both  malleable  and  ductile,  but  soft  and  per- 
fectly inelastic. 

The  fusing  point  of  lead  is  61 70  F.  Exposed  to  a 
high  heat,  it  absorbs  oxygen  rapidly,  forming  on  its  sur- 
face a  gray  film  of  protoxid  and  metallic  lead. 

Fusible    Alloys. — The    alloy    known    as    Rose's 


248  DENTAL   PROSTHESIS   AND    METALLURGY. 

Fusible  Metal  is  composed  of  two  parts  of  bismuth  to 
one  of  lead  and  one  of  tin,  and  melts  at  about  2000  F. 
A  still  more  fusible  alloy  is  composed  of  lead  3  parts, 
tin  2  parts,  and  bismuth  5  parts,  which  fuses  at  1970  F. 

Soft  solder  is  an  alloy  composed  of  lead  and  tin  in 
the  proportion  of  two  parts  of  the  former  to  one  of  the 
latter. 

Use  in  the  Laboratory. — Lead,  either  in  its  pure 
state  or  when  alloyed  with  certain  other  metals,  serves 
important  purposes  in  the  dental  laboratory.  In  its 
simple  or  uncombined  state  it  is  useful  only  in  forming 
counter-dies,  in  swaging  plates,  and  for  striking  up 
cusps  in  crown-  and  bridge-work.  Alloyed  with  anti- 
mony, with  the  addition,  sometimes,  of  very  small  por- 
tions of  copper,  tin,  and  bismuth,  it  forms  different 
grades  of  type-metal,  which  is  harder  than  lead  and 
very  brittle,  and  is  sometimes  used  for  dies. 


TIN. 

Symbol,  Sn  (Stannum).     Atomic  weighty  1 17-7- 

General  Properties. — Tin  is  a  brilliant,  silver- 
white  metal,  the  luster  of  which  is  not  sensibly  affected  by 
exposure  to  the  air,  but  is  easily  oxidized  by  heat.  It 
has  a  slightly  disagreeable  taste,  and  emits,  when  rubbed, 
a  peculiar  odor.  It  is  soft,  inelastic,  and  when  bent 
emits  a  peculiar  cracking  sound  called  "  the  creaking  of 
tin."  It  is  inferior  in  tenacity  and  ductility,  but  is 
very  malleable. 


COPPER.  249 

The  fusing  point  of  tin  is  about  4400  F.  ;  it  boils  at 
a  white  heat,  and  burns  with  a  blue  flame  to  binoxid. 

Dental  Uses. — In  its  pure  state,  it  is  sometimes 
used  for  counter-dies,  and  occasionally  for  dies.  When 
employed  for  the  latter  purpose  in  connection  with  a 
lead  counter,  the  latter  should  not  be  obtained  directly 
from  the  die,  as  the  high  temperature  of  melted  lead 
would  produce,  when  poured  upon  the  tin,  partial  fusion 
of  the  latter,  and  consequent  adhesion  of  the  two  pieces. 
Tin  is  also  used  by  many  operators  as  a  trial  base  plate  for 
artificial  dentures  instead  of  wax,  gutta-percha,  or  other 
more  pliable  materials. 


COPPER. 

Symbol,  Cu  (Cuprum).     Atomic  weight,   63.2. 

General  Properties. — Copper  is  of  a  brownish-red 
color,  with  a  tinge  of  yellow ;  has  a  faint  but  nauseous 
and  disagreeable  taste,  and  imparts  when  exposed  to 
friction  a  smell  somewhat  similar  to  its  taste.  It  is 
both  malleable  and  ductile,  but  excels  in  the  former 
property,  finer  leaves  being  obtained  from  it  than  wire. 
It  is  inferior  to  iron  in  tenacity,  but  surpasses  gold, 
silver,  and  platinum  in  this  respect. 

The  Fusing  Point. — Copper  fuses  at  about  20000  F. 

Alloys    of   Copper. — Copper   unites  readily    with 

most  metals,  forming  alloys  of  great  practical  value  in 

the  arts,  but  which  have  but  a  limited  application  in 

dental  laboratory  processes.     Many  of  these  alloys  are 

17 


250  DENTAL    PROSTHESIS    AND    METALLURGY. 

curious  and  instructive,  as  illustrating  the  singular  and 
unaccountable  influence  of  alloying  upon  the  distinctive 
properties  of  the  component  metals.  The  following  sum- 
mary embraces  the  names  and  composition  of  the  more 
familiar  alloys  of  copper,  omitting,  as  unnecessary  in  this 
connection,  a  description  of  their  individual  properties. 

Alloys  of  Copper  with  Zinc. — Brass  is  an  alloy 
of  uncertain  and  variable  composition,  consisting  usu- 
ally, however,  of  two  to  five  parts  of  copper  and  one 
of  zinc.  Brass  melts  at  18690  F.,  Prince's  Metal,  and 
its  allied  compounds,  Pinchbeck,  Similor,  and  Manheim 
gold,  consist  of  100  parts  of  copper  and  from  52  to  55 
of  zinc.  Dutch  gold,  from  which  foil  of  that  name 
was  formerly  obtained,  is  formed  of  11  parts  of  copper 
with  2  of  zinc. 

Brass  solder  consists  of  two  parts  of  brass  and  one 
of  zinc,  to  which  a  little  tin  is  occasionally  added. 

Alloys  of  Copper  with  Tin. — Bell  metal  usually 
consists  of  100  parts  of  copper  with  from  60  to  63  parts 
of  tin.  Cannon  metal  is  compounded  of  90  parts  of 
copper  with  10  of  tin. 

German  silver  is  composed  of  copper,  40.4  ;  nickel, 
31.6;  zinc,  25.4;  iron,  2.6;  but  the  proportion  of  the 
metals  of  this  alloy  differ  according  to  the  various  uses 
to  which  this  compound  is  applied. 

Babbitt  metal  is  a  compound  of  copper,  antimony, 
and  tin  in  about  the  following  proportions:  — 

Copper, 2  parts. 

Antimony, 3  parts. 

Tin, 12  parts. 


IRON.  251 

The  antimony  must  be  added  after  the  other  metals  are 
perfectly  fused  and  mixed. 

This  alloy-  is  used  in  the  dental  laboratory  for  dies, 
and  is  thought  by  many  to  be  superior  to  zinc  for  that 
purpose. 

IRON. 

Symbol,  Fe  (Ferrum).     Atomic  weight,  56. 

Occurrence. — Iron  is  rarely  found  in  a  metallic 
state  in  nature ;  the  compounds  of  iron,  however,  are 
distributed  in  great  abundance.  It  is  present  in  nearly 
all  forms  of  rock  and  earth,  and  imparts  various  shades 
of  color,  it  being  the  most  widely  diffused  natural 
mineral  coloring  material.  Iron  is  also  found  in  vary- 
ing proportions  in  most  of  the  vegetables,  and  is  a  very 
important  component  of  animal  tissue.  It  enters  into 
the  composition  of  the  human  blood  in  about  one  part 
per  thousand. 

Properties. — Pure  iron  in  compact  masses  has  a 
grayish-white  color,  is  tolerably  soft,  anrj  tough.  It 
does  not  oxidize  when  exposed  to  dry  air,  but  in  moist 
air  it  rusts  rapidly,  and  is  converted  into  ferric  oxid. 

At  ordinary  temperatures  it  is  one  of  the  most  rigid 
or  unyielding  of  metals,  but  by  heating  it  is  rendered 
so  ductile  that  it  may  be  rolled  into  thin  sheets  or  drawn 
into  the  finest  wire.  It  is  during  this  plastic  stage, 
through  which  it  always  passes  before  it  fuses,  that  two 
pieces  may  be  brought  together  and  made  to  cohere  by 
pressure  or  hammering,  the  process  known  as  welding. 


252  DENTAL    PROSTHESIS   AND    METALLURGY. 

It  is  not  upon  the  physical  properties  alone  that  the 
value  of  iron  depends,  as  it  enters  into  many  com- 
pounds which  are  of  much  use  to  the  arts,  and  its  chemi- 
cal relation  to  carbon  is  such  that  the  addition  of  a 
small  quantity  of  the  latter  will  convert  it  into  steel, 
which  is  harder  and  more  elastic  than  iron,  while  the 
addition  of  a  larger  quantity  of  carbon  produces  cast- 
iron,  which  is  more  fusible  and  brittle.  Thus  we  have 
three  distinct  grades  or  modifications  of  iron, — cast- 
iron,  wrought-iron,  and  steel. 

Fusing  Point. — The  fusing  point  of  pure  iron  is 
estimated  to  be  about  29000  F.,  while  the  amount  of 
carbon  introduced  in  forming  the  different  modifica- 
tions of  iron  relatively  reduces  the  point  of  fusion. 

Hardening  and  Tempering  Steel. — The  hard- 
ening of  steel  is  effected  by  subjecting  it  suddenly  to 
extremes  of  temperature.  Conversely,  the  hardened 
steel,  reheated  to  redness  and  allowed  to  cool  slowly,  is 
again  converted  into  soft  steel.  Any  desired  variation 
between  these  points  may  be  obtained  by  taking  the 
hardened  steel,  carefully  reheating  it  to  the  proper  point 
(see  table),  and  stopping  the  operation  at  that  moment 
by  suddenly  chilling  it ;  this  constitutes  tempering. 

In  writing  upon  this  subject  in  the  "American  Sys- 
tem of  Dentistry,"  Dr.  Kirk  directs  that  where  small 
articles,  such  as  drills,  excavators,  and  other  dental  in- 
struments, are  to  be  hardened,  they  should  always  re- 
ceive a  protective  coating  of  some  material  which  will 
retard  or  prevent  loss  of  carbon  by  oxidation  during 
the  heating  process.     Common  soap  answers  admirably 


IRON. 


253 


for  this  purpose.  After  being  heated  carefully  to  the 
proper  temperature,  which  has  been  previously  deter- 
mined by  experiment,  the  instrument  is  suddenly  chilled 
by  plunging  it  into  water  or  some  medium  which  will 
rapidly  abstract  its  heat.  Water  alone,  or  with  the  ad- 
dition of  small  proportions  of  acid  or  salt — the  first  to 
aid  in  the  separation  of  the  scale  of  oxid,  the  latter  to 
increase  conductivity — is  most  commonly  used,  though 
in  some  instances  where  extreme  hardness  is  desired 
mercury  is  used,  which,  on  account  of  its  superior  con- 
ductivity, chills  the  heated  metal  instantly.  With  water 
the  chilling  process  is  slower,  it  being  an  inferior  con- 
ductor, and  when  articles  of  considerable  size  in  a 
heated  state  are  plunged  into  it  actual  contact  of  the 
cold  water  is  prevented  for  a  moment  by  the  formation 
of  an  envelope  of  steam,  which  surrounds  the  hot  metal 
and  protects  it.  This  does  not  occur  when  the  mercury 
bath  is  used. 

The  approximate  temperatures  corresponding  to  the 
various  tints  are  shown  in  the  following  table : — 


Tem 

'EEATURE. 

Color. 

Temper. 

4300  to 

470°  . 

49°°   • 

450° 

F.  .   . 

Very  faint  y 
pale  straw, 

Full  yellow,  . 

Brown    with 
spots,      .    . 

Purple,       .    . 
Bright  blue, 
Full  blue,  .    . 
Dark  blue,    . 

ell 
P 

0  w 
li  r  p 

to 
le 

Lancets,  razors,  surgical  instru- 
ments, enamel  chisels. 

Excavators,  very  small  cold- 
chisels. 

Pluggers,  scissors,  pen-knives. 

5100 

5300 

Axes,    plane-irons,    saws,    cold- 
chisels,  etc. 
Table-knives,  large  shears. 
Swords,  watch-springs. 
Fine  saws,  augers. 
Hand  and  pit  saws. 

5500 

560° 

6oo° 

254  DENTAL   PROSTHESIS   AND    METALLURGY. 

ANTIMONY. 

Symbol,  Sb  (Stibium).     Atomic  weight,  120. 

General  Properties. — Antimony  is  of  a  silver- 
white  color  with  a  tinge  of  blue.  It  is  brittle  and  easily 
pulverized.  It  enters  as  an  ingredient  into  the  compo- 
sition of  type  and  stereotype  metal,  music  plates,  and 
Britannia  metal.  It  is  also  a  component  of  certain  fusible 
alloys  analogous  to  those  already  mentioned  under  the 
head  of  lead,  and  which,  in  the  form  of  a  die,  are  some- 
times used  on  account  of  their  slight  degree  of  shrink- 
age. 

The  fusing  point  of  antimony  is  8400  F.,  and  when 
heated  at  the  blowpipe  it  melts  with  great  readiness,  and 
diffuses  white  vapors,  emitting  an  odor  similar  to  garlic. 


BISMUTH. 

Symbol,  Bi  (Bismuthum).     Atomic  weight,  207.5. 

General  Properties. — Bismuth  is  a  white-colored 
metal,  resembling,  in  some  degree,  antimony.  It  is 
soft,  but  so  brittle  as  to  be  easily  pulverized. 

The  Fusing  Point. — Bismuth  fused  at  about  5100  F. 

Alloyed  with  Other  Metals. — Bismuth  has  the 
property,  in  a  high  degree,  of  increasing  the  fusi- 
bility of  the  metals  with  which  it  is  incorporated,  and 
is  a  common  ingredient  of  the  more  fusible  alloys,  some 
of  which  melt  in  boiling  water.  One  part  of  bismuth 
with  24  of  tin  is  malleable,  but  the  alloy  of  these  metals 


MERCURY.  255 

becomes  brittle  by  the  addition  of  more  bismuth.  Bis- 
muth unites  readily  with  antimony,  and,  in  the  propor- 
tion of  one  part  or  more  of  the  former  to  two  of  the 
latter,  it  expands  in  the  act  of  cooling. 


MERCURY. 

Symbol,  Hg  (Hydrargyrum).     Atomic  weight,  200. 

Occurrence. — Mercury  is  frequently  found  in  nature 
in  the  metallic  state.  It  is  sometimes  found  dissemi- 
nated through  the  vein-stone  in  mines  of  this  metal, 
and  trickling  from  crevices  in  the  ores.  It  is  also  found 
in  globules  disseminated  through  its  most  important 
ore,  its  sulphid,  or  cinnabar,  HgS,  which  is  the  prin- 
cipal source  of  its  supply. 

The  principal  mines  are  in  Spain,  Austria,  China,  Aus- 
tralia, and  California.  It  has  been  found  in  great 
abundance  and  of  remarkable  purity  in  the  California 
and  Australian  mines. 

Extraction. — Two  general  methods  for  extracting 
mercury  from  its  ore  are  in  use.  The  first  is  to  simply 
roast  the  cinnabar,  with  access  of  air,  which  converts 
the  sulphur  into  sulphurous  anhydrid  and  pure  mercury, 
liberated  in  the  form  of  vapor,  which  is  condensed  in 
suitable  receivers.  The  second  is  to  mix  the  sulphid 
with  lime  or  oxid  of  iron  and  distil  the  mixture.  The 
sulphur  combines  with  flux  to  form  calcium  or  iron 
sulphid  as  the  case  may  be.  The  mercurial  vapors  are 
condensed  as  before,  in  receivers. 


256  DENTAL    PROSTHESIS    AND    METALLURGY. 

General  Properties. — Mercury,  in  the  solidified 
condition,  is  malleable  and  ductile.  It  is  silvery-white  in 
color,  and  has  a  strong  metallic  luster.  It  is  readily 
distinguished  from  other  metals  by  its  liquidity,  which 
it  maintains  at  all  ordinary  temperatures.  It  is  soluble 
in  dilute  nitric  acid  and  hot  sulphuric  ;  insoluble  in 
hydrochloric  acid. 

Mercury  unites  more  or  less  readily  with  all  the  metals 
excepting  iron  and  platinum  ;  the  latter  metal  will  unite, 
however,  in  the  spongy  condition.  After  this  union  of 
mercury  with  another  metal  has  taken  piace  it  is  known 
as  amalgam. 

Fusing  Point. — Mercury  fuses  at  400  below  zero, 
F.  Above  this  temperature  it  is  fluid ;  it  boils  at 
660  F. 

Compounds. —  With  Oxygen  mercury  unites  to  form 
two  classes  of  compounds,  mercuric  and  mercurous 
oxids,  both  of  which  are  highly  poisonous.  With 
Chlorin  it  forms  two  compounds,  mercuric  chlorid 
(corrosive  sublimate)  and  mercurous  chlorid,  familiarly 
known  as  calomel.  With  Iodin  it  forms  two  com- 
pounds, mercuric  iodid  and  mercurous  iodid.  With 
Sulphur,  it  combines  to  form  sulphates  and  sulphids. 

Detection  of  Impurities. — Commercial  mercury 
is  never  quite  pure,  being  more  or  less  contaminated 
with  lead,  tin,  zinc,  etc.  A  trace  of  these  is  contained 
in  the  metal  as  it  is  made,  but  unscrupulous  dealers 
frequently  add  base  metals  to  increase  their  profits,  as  a 
considerable  amount  of  such  adulteration  can  take  place 
without  interfering  with  its  fluidity. 


AMALGAMS.  257 

To  detect  the  presence  of  foreign  metals,  allow  a 
large  globule  of  the  suspected  sample  to  roll  over  the 
surface  of  a  sheet  of  white  paper,  when,  if  the  metal  is 
impure,  it  will  leave  a  streak  of  dross  in  its  track, 
which  will  not  occur  when  it  is  absolutely  pure. 

Only  chemically  pure  mercury  should  be  employed  in 
the  preparation  of  dental  amalgams.  This  can  now  be 
obtained  from  reliable  dealers. 


AMALGAMS. 

Amalgam  is  the  name  given  to  an  alloy  of  mercury 
and  one  or  more  other  metals. 

Dental  Amalgams. — The  constituents  of  amalgams 
employed  in  dentistry  are  usually  silver,  tin,  gold,  and 
platinum  in  varying  proportions,  with  mercury.  Zinc, 
copper,  and  other  base  metals  are  sometimes  employed, 
according  to  many  different  formulae. 

Properties  Desirable  in  Dental  Amalgams. — 
An  alloy  for  dental  amalgam  should  possess  the  quali- 
ties of  strength  and  sharpness  of  edge ;  be  capable  of 
retaining  its  shape  and,  as  far  as  possible,  free  from  dis- 
coloration. It  is  also  evident  that  an  amalgam  liable  to 
expand  to  any  great  extent  or  contract  is  not  to  be  re- 
lied upon  as  a  filling  material. 

Discoloration  of  Amalgam  Fillings. — The  dis- 
coloration of  amalgam  fillings  in  the  mouth  is  largely 
due  to  the  formation  of  sulphids.  According  to  Essig,* 
the  fluids  of  the  mouth,  in  every  case  where  the  most 


258  DENTAL    PROSTHESIS    AND    METALLURGY. 

scrupulous  cleanliness  is  not  observed,  may  be  said  to 
contain  sulphur  in  combination  with  hydrogen,  as 
dihydric  sulphid  (H2S),  resulting  from  decomposition 
of  particles  of  food  having  a  lodgment  between  or  ad- 
hering to  the  teeth.  The  affinity  of  sulphur  for  both 
silver  and  mercury  is  so  active  that  we  may  reasonably 
assume  that  not  only  the  discoloration  of  amalgam  fill- 
ings, but  in  many  cases  their  failure  to  prevent  a  recur- 
rence of  decay,  is  due  to  the  action  of  that  element 
upon  the  alloy. 

Formation  of  Amalgam  Alloys. — An  alloy  con- 
sisting of  silver,  tin,  gold,  and  platinum  being  a  typical 
combination,  the  method  of  producing  the  same  will 
illustrate  the  process  sufficiently,  there  being  little 
modification  where  other  metals  are  used. 

The  plumbago,  or  graphite,  crucible  is  preferable  ;  it 
should  be  brought  to  a  bright-red  heat  and  a  sufficient 
quantity  of  borax  dropped  in  and  allowed  to  fuse  to  coat 
the  whole  inner  surface,  after  which  the  silver  and  gold, 
with  the  platinum  in  small  pieces,  should  be  introduced 
and  thoroughly  fused.  The  tin  is  then  added  and  the 
fluid  mass  poured  into  suitable  molds.  After  it  is 
thoroughly  cooled  it  may  be  brought  into  a  suitable 
state  for  use,  either  with  a  clean  file  or  with  a  chisel  in 
a  lathe. 

Composition  of  Standard  Alloys. — The  follow- 
ing table,  taken  from  Dr.  E.  C.  Kirk's  article  in  the 
"American    System    of    Dentistry,"    shows    the   com- 

*  Essig's  "Metallurgy." 


ALLOYS. 


259 


position  of  some  of  the  principal  dental  amalgam  alloys 
in  use  :  — 


Caulk's  Par-excellence,  .  .  . 
Dawson's  Superior  Amalgam, 

Essig's  Alloy, 

Fletcher's  P.  and  G.  Alloy,  . 
Flagg's  Contour  Alloy,  .  . 
Globe  (S.  S  White's),  .  .  .  . 
Hood    &    Reynold's    G.  and 

P.  Alloy 

Johnson   &    Lund's   Extra 

Amalgam, 

Justi's    Superior    G.    and    P. 

Alloy, 

King's  Occidental, 

Lawrence's  Amalgam,  .  .  .  . 
Peirce's  Dental  Alloy,  .  .  .  . 
Sibley's  G.  and  P.  Alloy,  .  . 
Townsend's  Improved,  .  .  . 
Welche's  G.  and  P.  Alloy, 


i 

S 

X 

Q 

0 

OS 
M 

6 

D 

Oh 

z 

H 

>i 

O 
O 

< 

Ph 
O 

N 

a 

in 

u 

U 

61.75 

27.25 

O.I5 

0.25 

10.60 

63-55 

31-85 

0.65 

0.15 

2.35 

i-45 

55- 

45- 

2.5 

2-5 

.    . 

50.35 

43  35 

3-35 

1.30 

1.65 

37- 

58. 

5- 

53-36 

44-74 

1.50 

0.40 

50.40 

44-3° 

3.80 

•30 

•  • 

1.20 

■_■ 

61.15 

36  75 

.15 

■So 

i-45 

59 -IO 

35.20 

0.32 

0.08 

3  5° 

1  80 

54-75 

42-75 

.    . 

2.50 

5Q-43 

44  06 

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40. 

55- 

4- 

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r. 

54-65 

43-IS 

0.20 

2  00 

54-5o 

44 -5o 

1. 

51-9° 

46.00 

1.70 

.40 

" 

ALLOYS,    THEIR    TREATMENT   AND 

BEHAVIOR  IN  THE  PROCESS  OF 

COMPOUNDING. 

General  Properties. — All  alloys  possess  metallic 
luster,  are  opaque,  conduct  heat  and  electricity,  and, 
in  a  greater  or  less  degree,  are  ductile,  malleable,  elas- 
tic, and  sonorous.  Some  alloys,  as  brass  and  gong 
metal,  are  usually  malleable  in  the  cold  and  brittle 
when  hot. 

Metals  sometimes  unite  in  atomic  ratios,  forming 
compounds  of  definite  or  equivalent  proportions  of  the 


260  DENTAL   PROSTHESIS   AND    METALLURGY. 

component  metals,  as  certain  alloys  of  copper  and  zinc, 
gold  and  copper,  gold  and  silver,  mercurial  alloys,  etc., 
while,  on  the  other  hand,  many  are  formed  in  all  pro- 
portions, like  mixtures  of  salt  and  water. 

Metals  differ  in  respect  to  their  affinity  for  each  other, 
and  do  not,  therefore,  alloy  with  equal  facility ;  thus 
it  is  difficult  to  unite  silver  and  iron,  but  the  former 
combines  readily  with  gold,  copper,  or  lead. 

The  ductility  of  an  alloy  is,  in  general,  less 
than  that  of  its  constituent  metals,  and  this  difference 
is,  in  some  instances,  remarkably  prominent,  as  in  the 
case  of  certain  alloys  of  copper  and  tin,  already  men- 
tioned. 

An  alloy  is  generally  harder  than  the  mean  hardness 
of  its  components,  a  property  which,  when  taken  in 
connection  with  their  increased  fusibility,  gives  to  al- 
loys peculiar  value  in  the  formation  of  dies  for  stamping 
purposes.  To  the  rule  stated,  amalgams,  or  mercurial 
alloys,  are  cited  as  exceptions. 

The  density  of  an  alloy  varies  with  the  peculiar 
metals  composing  it,  being  generally  either  greater  or 
less  than  the  mean  density  of  its  several  components. 

The  Fusing  Point. — It  is  impossible  to  predict 
with  certainty  the  melting  point  of  an  alloy  from  that 
of  its  separate  constituents,  but,  generally,  the  fusibil- 
ity of  the  alloy  is  increased,  sometimes  in  a  most  re- 
markable degree.  The  alloy  of  5  parts  of  bismuth,  3 
of  lead,  and  2  of  tin  is  a  striking  example  of  this  fact, 
this  compound  melting  at  1970,  while  the  mean  melt- 
ing point  of  its  constituents  is  5140.     Silver  solder  is 


ALLOYS.  26l 

also  a  familiar  illustration  of  the  influence  of  alloying 
on  the  fusibility  of  metals;  copper,  melting  at  1996°, 
and  silver  at  18730,  when  combined  fuse  at  a  heat 
much  below  that  required  to  melt  silver,  the  more  fusi- 
ble component  of  the  alloy.  Examples  might  be 
multiplied,  but  it  will  be  sufficient  to  add  that,  in 
general,  metallic  alloys  melt  at  a  lower  heat  than  is  re- 
quired to  fuse  the  most  refractory  or  infusible  component, 
and  sometimes  than  the  most  fusible  ingredient. 

The  color  of  an  alloy  cannot,  in  general,  be  in- 
ferred from  that  of  component  metals  ;  thus  it  would  "be 
conjectured  that  copper  would  be  rendered  very  much 
paler  by  adding  to  it  zinc  in  considerable  quantities, 
but  the  fallacy  of  such  an  inference  is  at  once  shown  by 
an  examination  of  some  of  the  rich-looking  gold-colored 
varieties  of  brass,  as  Prince's  metal,  pinchbeck,  and 
similor,  composed  each  of  nearly  equal  parts  of  copper 
and  zinc  ;  and  Manheim  gold,  compounded  of  3  parts 
copper  and  1  of  zinc. 

The  affinity  of  an  alloy  for  oxygen  is  greater 
than  that  of  the  separate  metals,  a  phenomenon  that  is 
ascribed  by  some,  to  the  increase  of  affinity  for  oxygen 
which  results  from  the  tendency  of  one  of  the  oxids  to 
combine  with  the  other ;  by  others  it  is  attributed  to 
galvanic  action.  According  to  Faraday,  100  parts  of 
steel  alloyed  with  one  of  platinum  is  dissolved  with 
effervescence  in  dilute  sulphuric  acid  too  weak  to  act 
with  perceptible  energy  on  common  steel.  It  is  offered 
in  explanation  of  this  fact  that  the  steel  is  rendered 
positive  by  the  presence  of  platinum. 


262  DENTAL   PROSTHESIS   AND    METALLURGY. 

Other  points  of  interest  will  suggest  themselves  in 
connection  with  the  behavior  of  alloys  in  the  process  of 
compounding. 


INDEX. 


ADHESION,  25,  113,  220 
Air-chamber,  manner  of  forming,  29 
Alloys,  general  properties,  etc.,  221, 

259 

gold,  223 

method  of  determining  carat, 
converting     into     required 
forms,  227 
Aluminum,   general   properties,   etc., 
243 

alloys  of,  246 
Alveolar  ridge,  lack  of  symmetry  in, 

Amalgams,  257 

formulae  for,  259 
Annealing,  109 

Antagonizing  models,  for  partial  den- 
tures, 39 

entire  dentures,  38 

upper  dentures,  36 
Antimony,  254 

Appliances   for  correcting  irregulari- 
ties, 167 
Application  of  gum  enamel,  146 
Arrangement  of  teeth,  57,  122 
Articulation,  securing,  35 
Artificial   dentures,  cast  metai  base, 
129 

celluloid  base,  85 

electro-deposit  base,  132 

rubber  base,  64 

swaged  base,  102 
Artificial  palates,  153 
Atomic  weight,  221 
Attaching  teeth  to  a  metallic  base  with 
rubber  or  celluloid,  147 


Babbitt  metal,  250 
Backing  teeth,  126 
Baker's  velum,  159 
Baking  furnaces,  143 
Beeswax,  20 
"  Best  "  celluloid  heater,  95 


Bismuth,  254 
Bridge-dentures,  209 

-splint,  17 
Brittleness  of  metals,  220 


Carving  the  model,  41 
Case's  enamel  cleaver,  iqo 
Cast  metal  base,  129 
Celluloid  base,  85, 

carving  for,  89 

composition  of,  87 

facing  to  other  bases,  100 

finishing  process,  99 

flasking  for,  91 

formula  for,  87 

grooves  or  gates,  92 

heater,  95 

metal  casts  for,  88 

molding,  103 

plaster  model,  30 

processes    preliminary    to   mold- 
ing, 102 
Clasps,  84,  110 

modification  in  form  of,  84 

uniting  the  plate  and,  111 

vulcanite  plate  attached  to,  147 
Cohesion,  220 
Conductivity  of  metals,  220 
Continuous-gum  work,  139 

applying  the  body,  142 

applying  the  gum  enamel,  146 

attaching  the  teeth,  141 

final  baking,  146 

first  baking,  142 

the  Sharp  furnace,  145 
Converting  gold  alloys  into  required 

forms,  223 
Copper,  general  properties,  etc.,  249 
Counter-dies,  metallic,  102 
Crown,  Downie,  202 

gold, 204 

Richmond,  189 


26 


264 


INDEX. 


Defects  in  palatine  organs,  151 
Dentimeter,  Weirich's,  192 
Dies,  metallic,  102,  108 
Ductility,  220 

Electro-deposit,  base,  132 
copper,  132 
gold,  137 
silver,   134 

preparation  of  batteries,  132,  137 
Elasticity  of  metals,  220 
Elements  employed  in  refining  gold, 

230 
Enamel  cleaver,  190 
Entire  dentures,  36 

antagonizing  wax  models,  38 
esthetic  requirements  in  the  selec- 
tion  and    arrangement   of    the 
teeth  for,  43 
table  of  temperaments,  52 
Esthetic  requirements  in  selecting  and 

arrangement  of  teeth,  43 
Examination  of  the  mouth,  11 

Faulty  articulation,  60 
Flasking  for  rubber,  65 

for  celluloid,  91 
Flasks  for  moulding,  105 
Formulas  for  Babbitt  metal,  250 

celluloid,  87 

gold  plate,  225 

gold  solders,  227 

silver  solders,  242 
Furnace,  Sharp's,  143 
Fusibility,  220 
Fusible  alloys,  129 

Gas  furnace,  Sharp's,  143 

Gates   or   outlet  grooves    in    flasking 

rubber,  69 
General  properties  of  alloys,  259. 
Gold,  properties  of,  222 

elements  employed  in  refining,  230 
formulas  for  plate  and  solder,  225, 

227 
influences  of  alloying,  222 
reduction  of,  to  lower  standard  of 

fineness,  228 
solders,  226 

to  raise  from  a  lower  to  a  higher 
standard,  228 
Grinding  and  articulating  teeth,  57 

Hardening  and  tempering  steel,  252 
Hardness  of  metals,  220 
Hawes  molding  flask,  105 
Heaters,  celluloid,  95 


Impression  cups  or  trays,  21-27 

Impressions  of  the  mouth,  20 
manner  of  taking,  20-29 
materials  used  for,  18-20 

Interdental  splints,  160 

Investing,  125 

Iridium,  239 

Iron,  general  properties,  etc.,  251 

Irregularities,  appliances  for  correct- 
ing, 167 


Jointing  gum  or  block  teeth,  63 


Kingsley's  artificial  velum,  151 
interdental  splint,  165 

Lead,  general  properties,  etc  ,  247 

use  in  laboratory,  248 
Lower  dentures,  118 

Malleability,  219 

Manner  of  removing  impressions,  24 
Materials  for  impressions,  18 
Mercury,    physical    properties,  ^tc, 

255 
Meial  casts  for  moulding  celluloid,  88 
Metallic   base    plate,    rubber   attach- 
ment, 147 

methods  of  making  attachments, 

149 
clasps  attached  to  rubber  plates, 

84 

dies  and  counter-dies,  102 
Metallurgy,  219 

Metals,  physical  properties  of,  219 
Method  of  taking  impressions,  20 
Modeling  composition,  19 
Models,  plaster,  30 
Molding,  materials  for,  102 

preparation  of  cast  for,  103 
Molecular  structure  of  metals,  219 

Obturators,  Baker's,  159 

Kingsley's,  151 

Suerson's,  156 
Oil,  objections  to,  32 
Ottolengui  root-facers,  186 

root  reamers,  188 


Packing  rubber,  71 

Palatal  organs,  defects  of,  151 

Partial  dentures,  120 

antagonizing  models  for,  39 


INDEX. 


265 


Pattern,  forming,  for  plate,  107 
Physical  properties  of  metals,  219 
Plaster  casts,  30 

from   an    impression   in   wax   or 
modeling  compound,  30 

from  an  impression  in  plaster,  31- 

34 

Plaster-of-Paris,  18 

derivation,  18 

method  of  hastening  setting,  21 

preparation  of,  18 
Platinum,  general  properties,  etc. ,  236 
Preparation  of  root  for  crowning,  185 
Preparing  the  vacuum  chamber,  29 


Reduction  of  gold  to  a  lower  standard 
of  fineness,  228 

of  gold  solders  to  proper  forms  for 
use,  226 
Refining  gold,  230 

silver,  240 
Re  posing  the  features,  44 
Retching,  treatment  of,  23 
Rimming  plate,  124 
Root  crowning,  185 
Rubber  as  a  dental  base,  64 

composition  of,  65 


Selecting  artificial  teeth,  43,  54 

Separating  fluids,  31,  34 

Separation  of  cast  from  impression,  32 

of  foreign  metals  from  gold,  230 
Shade  of  the  teeth,  42 
Shaping  the  cutting  edges  of  teeth,  60 
Silver,  general  properties  of,  239 

refining,  240 

solders,  242 
Solder,  gold,  226 


Solder,  silver,  242 
Soldering,  127 
Suerson's  obturator,  156 
Swaging  plates,  108 


Table  of  temperaments,  52 
Taking  the  bite,  35 
Tenacity,  220 

Tests  for  perfect  impression,  23 
The   teeth   as   indicated  by  tempera- 
ment, 49 
The  Philadelphia  vulcanizer,  77 
Tin,  general  properties,  etc.,  248 

dental  uses,  249 
Toughness  of  metals,  220 
Treatment  for  retching,  23 


Vacuum  chamber,  29,  115 
Varnish,  formulae  for,  34 

holder,  the  clover  leaf,  35 
Vulcanized  base  plate,  64 
finishing,  80 
flasking  for,  65 

outlet  grooves  or  gates,  69 

packing,  71 

pink  rubber  facing,  82 

vulcanizing,  73 
Vulcanizers,  76 


Wax,  yellow,  20 

white,  20 
Weirich's  enamel  cleaver,  191 
Welding,  221 


Zinc,  general  properties,  247 
use  for  dental  purposes,  247 


17 


No.  8  November,  1900 

A  Classified  Catalogue  of 
Books  on  Medicine  and  the 
Collateral  Sciences,  Phar- 
macy, Dentistry,  Chemistry, 
Hygiene,    Microscopy,    Etc. 


*&P 


P.  Blakiston's  Son  &  Company,  Pub- 
lishers of  Medical  and  Scientific  Books, 
1012    Walnut    Street,    Philadelphia 


SUBJECT    INDEX. 


Special  Catalogues  of  Books  on  Pharmacy,  Dentistry, 
Chemistry,  Hygiene,  and  Nursing  will  be  sent  free  upon 
application.  All  inquiries  regarding  prices,  dates  of  edition, 
terms,  etc.,  will  receive  prompt  attention. 


SUBJECT  PAGE 

Alimentary  Canal  (see  Surgery)  19 

Anatomy 3 

Anesthetics 14 

Autopsies  (see  Pathology) 16 

Bacteriology  (see  Pathology) .  16 

Bandaging  (see  Surgery) 19 

Blood,  Examination  of 16 

Brain  4 

Chemistry 4 

Children,  Diseases  of 6 

Climatology 14 

Clinical  Charts 6 

Compends 22,  23 

Consumption  (see  Lungs) n 

Cyclopedia  of  Medicine 8 

Dentistry 7 

Diabetes  (see  Urin.  Organs)..  21 

Diagnosis 17 

Diagrams  (see  Anatomy) 3 

Dictionaries,  Cyclopedias 8 

Diet  and  Food 14 

Dissectors 3 

Ear 9 

Electricity  9 

Emergencies  (see  Surgery) 19 

Eye 9 

Fevers 9 

Gout  10 

Gynecology  21 

Hay  Fever 20 

Heart 10 

Histology 10 

Hospitals  (see  Hygiene) 11 

Hydrotherapy 14 

Hygiene 11 

Insanity  4 

Intestines  (see  Miscellaneous)  14 
Latin,   Medical  (see  Miscella- 
neous and  Pharmacy) 14, 16 

Life  Insurance 14 

Lungs 12 

Massage 12 

Materia  Medica 12 

Medical  Jurisprudence 13 

Microscopy  13 

Milk  Analysis  (see  Chemistry)      4 


SUBJECT.  PAGE 

Miscellaneous  14 

Nervous  Diseases  14 

Nose 20 

Nursing 15 

Obstetrics.. 16 

Ophthalmology 9 

Organotherapy 14 

Osteology  (see  Anatomy) 3 

Pathology 16 

Pharmacy 16 

Physical  Diagnosis 17 

Physical  Training  (see  Miscel- 
laneous)    14 

Physiology  17 

Pneumotherapy 14 

Poisons  (see  Toxicology) 13 

Popular  Medicine 10 

Practice  of  Medicine 18 

Prescription  Books 18 

Refraction  (see  Eye) 9 

Rheumatism  10 

Sanitary  Science 11 

Skin .*...  19 

Spectacles  (see  Eye)  9 

Spine  (see  Nervous  Diseases)  14 
Stomach  (see Miscellaneous)...  14 

Students'  Compends 22,  23 

Surgery    and     Surgical     Dis- 
eases    19 

Syphilis 21 

Technological  Books 4 

Temperature  Charts 6  ' 

Therapeutics 12 

Throat  20 

Toxicology 13 

Tumors  (see  Surgery) iq 

U.  S.  Pharmacopoeia 17 

Urinary  Organs 20 

Urine 20 

Venereal  Diseases 21 

.Veterinary  Medicine 21 

Visiting  Lists,  Physicians'. 
{Send  for  Special  Circular.) 

Water  Analysis 11 

Women,  Diseases  of. 21 


f$^°  The  prices  as  given  in  this  Catalogue  are  net.  Cloth 
bindings  unless  otherwise  specified.  Postpaid,  upon  receipt 
of  advertised  price. 


SUBJECT  CATALOGUE  OF  MEDICAL   BOOKS.  3 

SPMCIAI,  NOTM. — The  prices  given  in  this  catalogue  are 
absolutely  net,  no  discount  can  be  allowed  retail  purchasers  under  any 
consideration.  This  rule  has  been  established  in  order  that  everyone 
will  be  treated  alike,  a  general  reduction  in  former  prices  having  been 
made  to  meet  previous  retad  discounts.  Upon  receipt  of  the  advertised 
price  any  book  will  be  forwarded  by  mail  or  express,  all  charges 
prepaid. 

ANATOMY. 

MORRIS.     Text-Book   ot   Anatomy.    2d   Edition.     Revised  and 

Enlarged.     790   Illustrations,  214   of    which   are   printed  in  coiors. 

.  Cloth,  $6. 00 ;  Leather,  #7.00;  Half  Russia,  $8.00 

"  The  ever-growing  popularity  of  the  book  with  teachers  and  students 

is  an  index  of  its  value,  and  it  may  safely  be  recommended  to  all  inter- 
ested."— Medical  Record,  New  York. 

4®*  Sample  pages  and  illustrations  will  be  sent  free  to  any  address. 

BROOMELL.  Anatomy  and  Histology  of  the  Human  Mouth 
and  Teeth.     284  Illustrations.  $4  50 

DEAVER.  Surgical  Anatomy.  A  Treatise  on  Human  Anatomy 
in  its  Application  to  Medicine  and  Surgery.  With  about  400  very 
Handsome  full-page  Illustrations  Engraved  from  Original  Drawings 
made  by  special  Artists  from  dissections  prepared  for  the  purpose. 
Three  Volumes.  Royal  Square  Octavo. 
Cloth,  $2100;   Half  Morocco  or  Sheep,  $24. 00;  Half  Russia,  $27  00 

ECKLEY.  Practical  Anatomy.  A  Manual  for  use  in  the  Dissect- 
ing Room.  Based  upon  Morris'  Text-Book  of  Anatomy  and  Including 
a  Section  on  the  Fundamental  Principles  of  Anatomy.  With  347 
Illustrations,  many  of  which  are  in  colors.  Cloth,  $3  50;  Oil  Cloth,  $4.00 

GORDINIER.  Anatomy  of  the  Central  Nervous  System. 
With  271  Illustrations,  many  of  which  are  original.  Cloth,  #6.00 

HEATH.     Practical  Anatomy.     8th  Edition.    300  Illus.  $4.25 

HOLDEN.  Anatomy.  A  Manual  of  the  Dissections  of  the  Human 
Body.  Carefully  Revised  by  A.  Hewson,  m.d.,  Demonstrator  of 
Anatomy,  Jefferson  Medical  College.  Philadelphia.  Over  300  hand- 
some Illustrations.  7th  Edition.  In  two  compact  i2mo  Volumes, 
Large  New  Type.     Bound  in  Oil  Cloth,  price  of  each  Volume,  #1.50 

HOLDEN.  Human  Osteology.  Comprising  a  Description  of  the 
Bones,  with  Colored  Delineations  of  the  Attachments  of  the  Muscles. 
The  General  and  Microscopical  Structure  of  Bone  and  its  Develop- 
ment.   With  Lithographic  Plates  and  numerous  Illus.    8th  Ed.     $5.25 

HOLDEN.     Landmarks.     Medical  and  Surgical.     4th  Ed.  .75 

MACALISTER.  Human  Anatomy.  Systematic  and  Topograph- 
ical, including  the  Embryology,  Histology,  and  Morphology  of  Man. 
With  Special  Reference  to  the  Requirements  of  Practical  Surgery  and 
Medicine.    816  Illustrations.  Cloth,  $5.00  ;  Leather,  $6.00 

MARSHALL.  Physiological  Diagrams.  Life  Size.  Colored. 
Eleven  Life-Size  Diagrams  (each  seven  feet  by  three  feet  seven 
inches).     Designed  for  Demonstration  before  the  Class. 

In  Sheets,  Unmounted,  $40.00;  Backed  with  Muslin  and  Mounted 
on  Rollers,  $60.00 ;  Ditto,  Spring  Rollers,  in  Handsome  Walnut  Wall 
Map  Case,  $100.00;  Single  Plates — Sheets,  $5.00 ;  Mounted,  $7.50. 
Explanatory  Key,  .50.     Purchaser  must  pay  freight  charges. 

POTTER.  Compend  of  Anatomy,  Including  Visceral  Anatomy. 
6th  Ed.    16  Lith.  Plates  and  117  other  Illus.     .80  ;  Interleaved,  $1.00 

WILSON.     Anatomy,     nth  Edition.     429  Illus.,  26  Plates.      $5.00 

WINDLE.     Surface  Anatomy.     Colored  and  other  Illus.        $1.00 


SUBJECT  CATALOGUE. 


BRAIN  AND  INSANITY  (see  also 
Nervous  Diseases). 

BLACKBURN.  A  Manual  of  Autopsies.  Designed  for  the  Use 
of  Hospitals  for  the  Insane  and  other  Public  Institutions.  Ten  full- 
page  Plates  and  other  Illustrations.  $1.25 

GORDINIER.  The  Gross  and  Minute  Anatomy  of  the  Central 
Nervous  System.  With  many  full-page  and  other  Illustrations. 
8vo.  Cloth,  $6.00;  Sheep,  $7.00 

HORSLEY.  The  Brain  and  Spinal  Cord.  The  Structure  and 
Functions  of.     Numerous  Illustrations.  $2.50 

LEWIS  (BEVAN).  Mental  Diseases.  A  Text-Book  Having 
Special  Reference  to  the  Pathological  Aspects  of  Insanity.  26  Litho- 
graphic Plates  and  other  Illustrations.     2d  Ed.     Just  Ready.    $7.00 

MANN.  Manual  of  Psychological  Medicine  and  Allied 
Nervous  Diseases,  $3.00 

REGIS.  Mental  Medicine.  Authorized  Translation  by  H.  M. 
Bannister,  m.d.  $2.00 

SHUTTLEWORTH.  Mentally  Deficient  Children.  New 
Edition.  $i-5o 

STEARNS.  Mental  Diseases.  With  a  Digest  of  Laws  Relating 
to  Care  of  Insane.     Illustrated.  Cloth,  $2.75  ;  Sheep,  $3.25 

TUKE.  Dictionary  of  Psychological  Medicine.  Giving  the 
Definition,  Etymology,  and  Symptoms  of  the  Terms  used  in  Medical 
Psychology,  with  the  Symptoms,  Pathology,  and  Treatment  of  the 
Recognized  Forms  of  Mental  Disorders.     Two  volumes.  $10.00 

WOOD,  H.  C.    Brain  and  Overwork.  .40 

CHEMISTRY  AND  TECHNOLOGY. 

Special  Catalogue  of  Chemical  Books  sent  free  upon  application. 

ALLEN.  Commercial  Organic  Analysis.  A  Treatise  on  the 
Modes  of  Assaying  the  Various  Organic  Chemicals  and  Products 
Employed  in  the  Arts,  Manufactures,  Medicine,  etc.,  with  concise 
methods  for  the  Detection  of  Impurities,  Adulterations,  etc.  8vo. 
Vol.  I.  Alcohols,  Neutral  Alcoholic  Derivatives,  etc.,  Ethers,  Veg- 
etable Acids,  Starch,  Sugars,  etc.     3d  Edition,  by  Henry  Leff- 

MANN,  M.  D.  #4-50 

Vol.  II,  Part  I.  Fixed  Oils  and  Fats,  Glycerol,  Explosives,  etc. 
3d  Edition,  by  Henry  Leffmann,    m.  d.  $3-5° 

Vol.  II,  Part  II.  Hydrocarbons,  Mineral  Oils,  Lubricants,  BTzenes, 
Naphthalenes  and  Derivatives,  Creosote,  Phenols,  etc.  3d  Edition, 
by  Henry  Leffmann,  m.u.  $3-5° 

Vol.  II,  Part  III.  Terpenes,  Essential  Oils,  Resins,  Camphors,  etc. 
3d  Edition,  by  Henry  Leffmann,  m.d.  Preparing. 

Vol.  Ill,  Part  I.  Tannins,  Dyes  and  Coloring  Matters.  3d  Edition. 
Enlarged  and  Rewritten  by  J.  Merritt  Matthews,  ph.d.,  of  the 
Philadelphia  Textile  School.     Illustrated.  $4£o 

Vol.  Ill,  Part  II.  The  Amines,  Hydrazines  and  Derivatives, 
Pyridine  Bases.  The  Antipyretics,  etc.  Vegetable  Alkaloids,  Tea, 
Coffee,  Cocoa,  etc.     8vo.     2d  Edition.  $4. 50 

Vol.  Ill,  Part  III.  Vegetable  Alkaloids,  Non-Basic  Vegetable  Bitter 
Principles.  Animal  Bases,  Animal  Acids,  Cyanogen  Compounds, 
etc.     2d  Edition,  8vo.  $4-50 

Vol.  IV.     The  Proteids  and  Albuminous  Principles.     2d  Ed.      $4.50 

ALLEN.    Albuminous  and  Diabetic  Urine.    Illustrated.    #2.25 


MEDICAL   BOOKS. 


BARTLEY.  Medical  and  Pharmaceutical  Chemistry.  A 
Text-Book  for  Medical,  Dental,  and  Pharmaceutical  Students.  With 
Illustrations,  Glossary,  and  Complete  Index.  5th  Edition,  carefully 
Revised.  Cloth,  $3.00  j  Sheep,  $3.50 

BARTLEY.  Clinical  Chemistry.  The  Examination  of  Feces, 
Saliva,  Gastric  Juice,  Milk,  and  Urine.  Si. 00 

BLOXAM.  Chemistry,  Inorganic  and  Organic.  With  Experi- 
ments. 8th  Ed.,  Revised      281  Engravings.    Clo.,  84.25;  Lea.,  $5. 25 

CALDWELL.  Elements  of  Qualitative  and  Quantitative 
Chemical  Analysis.     3d  Edition,  Revised.  81.00 

CAMERON.     Oils  and  Varnishes.     With  Illustrations.  82.25 

CAMERON.     Soap  and  Candles.     54  Illustrations  82.00 

CLOWES  AND  COLEMAN.  Quantitative  Analysis.  5th 
Edition.     122  Illustrations.    Just  Ready.  S3. 50 

CONGDON.    Laboratory  Instructions  in  Chemistry.   In  Press. 

GARDNER.  The  Brewer,  Distiller,  and  Wine  Manufac- 
turer.    Illustrated.  81.50 

GARDNER.     Bleaching,  Dyeing,  and  Calico  Printing.       81.50 

GROVES  AND  THORP.     Chemical  Technology.     The  Appli- 
cation of   Chemistry  to  the  Arts  and   Manufactures. 
Vol.  I.  Fuel  and  Its  Applications.     607  Illustrations  and  4  Plates. 

Cloth,  85.00;  y2  Mor  ,  86.50 
Vol.  II.   Lighting.      Illustrated.  Cloth,  84.00:   y>  Mor.,  $5.50 

Vol.111.  G  s  Lighting.  Cloth, $3.50;  %  Mor.,  84. <o 

Vol.  IV.   Electric  Lighting.  In  Press. 

HOLLAND.  The  Urine,  the  Gastric  Contents,  the  Common 
Poisons,  and  the  Milk.  Memoranda,  Chemical  and  Microscopi- 
cal, for  Laboratory  Use.     6th  Ed.     Illustrated  and  interleaved,  81.00 

LEFFMANN.  Compend  of  Medical  Chemistrv,  Inorganic 
and  Organic.  Including  Urine  Analysis.  4th  Editiion,  Rewritten 
and  Revised.  .80;  Interleaved,  81.00 

LEFFMANN.      Analysis   of   Milk    and   Milk    Products.      2d 
Edition,  Enlarged.     Illustrated.  81.25 

LEFFMANN.  Water  Analysis.  For  Sanitary  and  Technic  Pur- 
poses.    Illustrated.     4th  Edition.  81.25 

LEFFMANN.  Structural  Formulae.  Including  180  Structural 
and  Stereo-Chemical  Formulae.     i2mo.     Interleaved.  81.00 

MUTER.  Practical  and  Analytical  Chemistry.  2d  American 
from  the  Eighth  English  Edition  Revised  to  meet  the  requirements 
of  American  Students.     56  Illustrations.    .  8125 

OETTEL.     Exercises  in  Electro-Chemistry.     Illustrated.        .75 

OETTEL.     Electro-Chemical  Experiments.     Illustrated.         .75 

RICHTER.     Inorganic  Chemistry.    5th  American  from  10th  Ger- 
man  Edition.     Authorized  translation  by  Edgar  F.   Smith,  m.a. 
ph.d.     89  Illustrations  and  a  Colored  Plate.  '  81.75 

RICHTER.  Organic  Chemistry.  3d  American  Edition.  Trans, 
from  the  8th  German  by  Edgar  F.  Smith.  Illustrated.  2  Volumes. 
Vol.    I.    Aliphatic  Series.     625  Pages.  S3. 00 

Vol.  II.    Carbocyclic  Series.     671  Pages.  83.00 

SMITH.  Electro-Chemical  Analysis.  2d  Edition,  Revised.  28 
Illustrations.  81.2  s 

SMITH  AND  KELLER.  Experiments.  Arranged  for  Students 
in  General  Chemistry.     4th  Edition.     Illustrated.    Just  Ready.      .60 


6  SUBJECT  CATALOGUE. 

SUTTON.  Volumetric  Analysis.  A  Systematic  Handbook  for 
the  Quantitative  Estimation  of  Chemical  Substances  by  Measure, 
Applied  to  Liquids,  Solids,  and  Gases.  8th  Edition,  Revised.  112 
Illustrations.    Just  Ready.  $5.00 

SYMONDS.     Manual   of  Chemistry,   for   Medical   Students. 

2d  Edition.  $2.00 

TRAUBE.  Physico-Chemical  Methods.  Translated  by  Hardin. 
97  Illustrations.  $1.50 

THRESH.     Water  and  Water  Supplies.     2d  Edition.  $2.00 

ULZER  AND   FRAENKEL.     Chemical  Technical  Analysis. 

Translated  by  Fleck.     Illustrated.  $1.25 

WOODY.     Essentials    of    Chemistry    and    Urinalysis.      4th 

Edition,     Illustrated.  $1.50 

***  Special  Catalogue  of  Books  on  Chemistry  free  upon  application . 

CHILDREN. 

CAUTLEY.     Feeding  of  Infants  and  Young  Children  by  Nat- 
ural and  Artificial  Methods.  $2.00 
HALE.     On  the  Management  of  Children.  .50 

HATFIELD.      Compend  of  Diseases   of   Children.      With    a 

Colored  Plate.     2d  Edition.  .80  ;    Interleaved,  $1.00 

MEIGS.  Infant  Feeding  and  Milk  Analysis.  The  Examination 
of  Human  and  Cow's  Milk,  Cream,  Condensed  Milk,  etc.,  and 
Directions  as  to  the  Diet  of  Young  Infants.  .50 

POWER.  Surgical  Diseases  of  Children  and  their  Treat- 
ment by  Modern  Methods.     Illustrated.  $2.50 

SHUTTLEWORTH.  Mentally  Deficient  Children.  New 
Edition.  $i-5° 

STARR.  The  Digestive  Organs  in  Childhood.  The  Diseases  of 
the  Digestive  Organs  in  Infancy  and  Childhood.  With  Chapters  on 
the  Investigation  of  Disease  and  the  Management  of  Children.  3d 
Edition,  Enlarged.  Illustrated  by  two  Colored  Plates  and  numerous 
Wood  Engravings.  In  Preparation. 

STARR.  Hygiene  of  the  Nursery.  Including  the  General  Regi- 
men and  Feeding  of  Infants  and  Children,  and  the  Domestic  Manage- 
ment of  the  Ordinary  Emergencies  of  Early  Life,  Massage,  etc.  6th 
Edition.     25  Illustrations.  $1.00 

SMITH.     Wasting  Diseases  of  Children.     6th  Edition.        $2.00 

TAYLOR  AND  WELLS.  The  Diseases  of  Children.  Illus- 
trated.    A  New  Manual.     746  pages.  $4.00 

CLINICAL  CHARTS. 

GRIFFITH.  Graphic  Clinical  Chart  for  Recording  Temper- 
ature, Respiration,  Pulse,  Day  of  Disease,  Date,  Age,  Sex, 
Occupation,  Name,  etc.  Printed  in  three  colors.  Sample  copies 
free.  Put  up  in  loose  packages  of  fifty,  .50.  Price  to  Hospitals,  500 
copies,  $4.00;  1000  copies,  $7.50.  With  name  of  Hospital  printed 
on,  .50  extra. 

KEEN'S  CLINICAL  CHARTS.  Seven  Outline  Drawings  of  the 
Body,  on  which  may  be  marked  the  Course  of  Disease,  Fractures, 
Operations,  etc.  Pads  of  fifty,  JSi.co.  Each  Drawing  may  also  be 
had  separately,  twenty-five  to  pad,  25  cents. 


MEDICAL   BOOKS. 


SCHREINER.     Diet    Lists.     Arranged   in   the  form   of  a   chart. 
With  Pamphlets  of  Specimen  Dietaries.     Pads  of  50.  .75 


DENTISTRY. 

Special  Catalogue  of  Dental  Books  sent  free  upon  application. 

BARRETT.  Dental  Surgery  for  General  Practitioners  and 
Students  of  Medicine  and  Dentistry.  Extraction  of  Teeth, 
etc.     3d  Edition.     Illustrated.  Nearly  Ready. 

BROOMELL.  Anatomy  and  Histology  of  the  Human  Mouth 
and  Teeth.     284  Handsome  Illustrations.  $4-50 

FILLEBROWN.      A    Text-Book    of    Operative     Dentistry. 

Written  by  invitation  of  the  National  Association  of  Dental  Facul- 
ties.    Illustrated.  $2.25 
QORGAS.     Dental  Medicine.     A  Manual  of  Materia  Medica  and 
Therapeutics.     6th  Edition,  Revised.          Cloth,  #4.00;  Sheep,  $5.00 

HARRIS.  Principles  and  Practice  of  Dentistry.  Including 
Anatomy,  Physiology,  Pathology,  Therapeutics,  Dental  Surgery, 
and  Mechanism.  13th  Edition.  Revised  by  F.  J.  S.  Gorgas,  m.d., 
d.d.s.     1250  Illustrations.  Cloth,  #6.00;  Leather,  $7.00 

HARRIS.  Dictionary  of  Dentistry.  Including  Definitions  of  Such 
Words  and  Phrases  of  the  Collateral  Sciences  as  Pertain  to  the  Art  and 
Practice  of  Dentistry.  6th  Edition.  Revised  and  Enlarged  by  Fer- 
dinand F.  S.  Gorgas,  m.d.,  d.d.s.         Cloth,  $5.00;  Leather,  $6.00 

HEATH.  Injuries  and  Diseases  of  the  Jaws.  4th  Edition.  187 
Illustrations.  $4.50 

HEATH.     Lectures  on   Certain    Diseases   of    the  Jaws.      64 

Illustrations.  Boards,  .50 

RICHARDSON.  Mechanical  Dentistry.  7th  Edition.  Thor- 
oughly Revised  and  Enlarged  by  Dr.  Geo.  W.  Warren.  691  Illus- 
trations. Cloth,  $5.00;  Leather,  $6.00 

SMITH.     Dental  Metallurgy.     Illustrated.  $1.75 

TAFT.     Index  of  Dental  Periodical  Literature.  $2.00 

TALBOT.     Irregularities  of  the  Teeth  and  Their  Treatment. 

2d  Edition.     234  Illustrations.  #3.00 

TOMES.     Dental  Anatomy.    Human  and  Comparative.    263  Illus- 
trations.    5th  Edition.  #4.00 
TOMES.     Dental  Surgery.     4th  Edition.     289  Illustrations.     #4.00 

WARREN.  Compend  of  Dental  Pathology  and  Dental  Medi- 
cine.    With  a  Chapter  on  Emergencies.     3d  Edition.     Illustrated. 

.80;  Interleaved,  #1.25 
WARREN.  Dental  Prosthesis  and  Metallurgy.  129  Ills.  $1.25 
WHITE.     The  Mouth  and  Teeth.     Illustrated.  40 

***  Special  Catalogue  0/  Dental  Books  free  upon  application. 


SUBJECT   CATALOGUE. 


DICTIONARIES. 

GOULD.  The  Illustrated  Dictionary  of  Medicine,  Biology, 
and  Allied  Sciences.  Being  an  Exhaustive  Lexicon  of  Medicine 
and  those  Sciences  Collateral  to  it:  Biology  (Zoology  and  Botany), 
Chemistry,  Dentistry,  Parmacology,  Microscopy,  etc.,  with  many 
useful  Tables  and  numerous  fine  Illustrations.  1633  pages.  5th  Ed. 
Sheep  or  Half  Dark  Green  Leather,  £10.00;   Thumb  Index,  $11.00 

Half  Russia,  Thumb  Index,  $12.00 

GOULD.  The  Medical  Student's  Dictionary,  nth  Edition. 
Illustrated.  Including  all  the  Words  and  Phrases  Generally  Used 
inMedicine,  with  their  Proper  Pronunciation  and  Definition,  Based 
on  Recent  Medical  Literature.  With  a  new  Table  of  Eponymic 
Terms  and  Tests  and  Tables  of  the  Bacilli,  Micrococci,  Mineral 
Springs,  etc.,  of  the  Arteries,  Muscles,  Nerves,  Ganglia,  Plexuses,  etc. 
nth  Edition.  Enlarged  by  over  ioo  pages  and  illustrated  with  a 
large  number  of  engravings.     S40  pages.    Just  Ready. 

Half  Green  Morocco,  $2.-0;    Thumb  Index,  $3  co 

GOULD.  The  Pocket  Pronouncing  Medical  Lexicon.  4th  Edi- 
tion. (30,000  Medical  Words  Pronounced  and  Defined.)  Containing 
all  the  Words,  their  Definition  and  Pronunciation,  that  the  Medical, 
Dental,  or  Pharmaceutical  Student  Generally  Comes  in  Contact 
With ;  also  Elaborate  Tables  of  Eponymic  Terms.  Arteries,  Muscles, 
Nerves,  Bacilli,  etc.,  etc.,  a  Dose  List  in  both  English  and  Metric 
Systems,  etc.,  Arranged  in  a  Most  Convenient  Form  for  Reference  and 
Memorizing.  A  new  (Fourth)  Edition,  Revised  and  Enlarged. 
838  pages.     Just  Ready. 

Full  Limp  Leather,  Gilt  Edges,  $1.00  ;  Thumb  Index,  $1.25 

100.000  Copies  of  Gould's  Dictionaries  Have  Been  Sold. 

GOULD  AND  PYLE.  Cyclopedia  of  Practical  Medicine  and 
Surgery.  Seventy-two  Special  Contributors.  Illustrated. 
One  Volume.  A  Concise  Reference  Handbook,  Alphabetically 
Arranged,  of  Medicine,  Surgery,  Obstetrics,  Materia  Medica, 
Therapeutics,  and  the  Various  Specialties,  with  Particular  Reference 
to  Diagnosis  and  Treatment.  Compiled  under  the  Editorial  Super- 
vision of  George  M.  Gould,  m.d.,  Author  of  "  An  Illustrated 
Dictionary  of  Medicine"  :  Editor  "  Philadelphia  Medical  Journal," 
etc.;  and  Walter  L.  Pyle.  m.d.,  Assistant  Surgeon  Wills  Eye 
Hospital ;  formerly  Editor  "  International  Medical  Magazine,"  etc., 
and  Seventy-two  Special  Contributors.  With  many  Illustrations. 
Large  Square  Svo,  to  correspond  with  Gould's  "  Illustrated  Dic- 
tionary." Just  Ready.  Full  Sheep  or  Half  Dark-Green  Leather,  $10. co 
With  Thumb  Index,  $11.00;  Ha  f  Russia,  Thumb  Index,  $12. co  net. 
***  Sample  Pages   and    Illustrations  and    Descriptive   Circulars   of 

Gould's  Dictionaries  and  Cyclopedia  sent  free  upon  application. 

HARRIS.  Dictionary  of  Dentistry.  Including  Definitions  ol  Such 
Words  and  Phrases  of  the  Collateral  Sciences  as  Pertain  to  the  Art 
and  Practice  of  Dentistry.  6th  Edition.  Revised  and  Enlarged  by 
Ferdinand  J.  S.  Gorgas,  m.d.,  d.d.s.   Cloth,  $5.00;  Leather,  $6  00 

LONGLEY.  Pocket  Medical  Dictionary.  With  an  Appendix, 
containing  Poisons  and  their  Antidotes,  Abbreviations  used  in  Pre- 
scriptions, etc.  Cloth,  .75;  Tucks  and  Pocket,  $1.00 

MAXWELL.  Terminologia  Medica  Polyglotta.  By  Dr. 
Theodore  Maxwell,  Assisted  by  Others.  $3°o 

The  object  of  this  work  is  to  assist  the  medical  men  ot  any  nationality 

in   reading   medical  literature   written   in  a  language  not   their  own. 

Each  term  is  usually  given  in  seven  languages,  viz.  :  English,  French, 

German,  Italian,  Spanish,  Russian,  and  Latin. 

TREVES  AND  LANG.    German-English  Medical  Dictionary  . 

Half  Russia,  $3.25 


MEDICAL  BOOKS. 


EAR  (see  also  Throat  and  Nose). 
BURNETT.     Hearing  and  How  to  Keep  It.     Illustrated.  .40 

DALBY,  Diseases  and  Injuries  of  the  Ear.  4th  Edition.  38 
Wood  Engravings  and  8  Colored  Plates.  $2.50 

HOVELL.  Diseases  of  the  Ear  and  Naso-Pharynx.  Includ- 
ing Anatomy  and  Physiology  of  the  Organ,  together  with  the  Treat- 
ment of  the  Affections  of  the  Nose  and  Pharynx  which  Conduce  to 
Aural  Disease.     122  Illustrations.     2d  Edition.  Preparing. 

PRITCHARD.  Diseases  of  the  Ear.  3d  Edition,  Enlarged. 
Many  Illustrations  and  Formulae.  #1.50 

WOAKES.     Deafness,  Giddiness,  and    Noises   in   the   Head. 

4th  Edition.     Illustrated.  $2.00 

ELECTRICITY. 

BIGELOW.  Plain  Talks  on  Medical  Electricity  and  Bat- 
teries. With  a  Therapeutic  Index  and  a  Glossary.  43  Illustra- 
tions.    2d  Edition.  $1.00 

HEDLEY.  Therapeutic  Electricity  and  Practical  Muscle 
Testing.     99  Illustrations.    Just  Ready.  $2.50 

JACOBI.     Electrotherapy.     Illustrated.  In  Press. 

JONES.    Medical  Electricity.   3d  Edition.    117  Illus.  #300 

MASON.    Medical  Electricity.     Numerous  Illustrations.  .75 


EYE. 

A  Special  Circular  oj  Books  on  the  Eye  sent  free  upon  application 

DONDERS.  The  Nature  and  Consequences  of  Anomalies  of 
Refraction.     With  Portrait  and  Illustrations.     Half  Morocco,  $1. 25 

FICK.  Diseases  of  the  Eye  and  Ophthalmoscopy.  Trans- 
lated by  A.  B.  Hale,  m.  d.  157  Illustrations,  many  of  which  are  in 
colors,  and  a  glossary.  Cloth,  $4.50  ;  Sheep,  $5.50 

GOULD  AND  PYLE.  Compend  of  Diseases  of  the  Eye  and 
Refraction.  Including  Treatment  and  Operations,  and  a  Section 
on  Local  Therapeutics.  With  Formulas,  Useful  Tables,  a  Glossary, 
and  in  Illus.,  several  of  which  are  in  colors.     2d  Edition,  Revised. 

Cloth,  .80;  Interleaved,  $1.00 

GOWERS.  Medical  Ophthalmoscopy.  A  Manual  and  Atlas 
with  Colored  Autotype  and  Lithographic  Plates  and  Wood-cuts, 
Comprising  Original  Illustrations  of  the  Changes  of  the  Eye  in  Dis- 
eases of  the  Brain,  Kidney,  etc.     3d  Edition.  $4.00 

HARLAN.     Eyesight,  and  How  to  Care  for  It.     Illus.  .40 

HARTRIDGE.     Refraction.     104   Illustrations    and   Test   Types 
10th  Edition,  Enlarged.    Just  Ready.  #1.50 

HARTRIDGE.  On  the  Ophthalmoscope.  3d  Edition.  With 
4  Colored  Plates  and  68  Wood-cuts.  $1.50 

HANSELL  AND  REBER.  Muscular  Anomalies  of  the  Eye. 
Illustrated.  #1.50 

HANSELL  AND  BELL.  Clinical  Ophthalmology.  Colored 
Plate  of  Normal  Fundus  and  120  Illustrations.  $1.50 

JESSOP.  Manual  of  Ophthalmic  Surgery  and  Medicine.  Col- 
ored Plates  and  108  other  Illustrations.  Cloth,  $3.00 


10  SUBJECT  CATALOGUE. 

MORTON.     Refraction  of  the  Eye.     Its  Diagnosis  and  the  Cor- 
rection of  its  Errors.     6th  Edition.  $1.00 

OHLEMANN.     Ocular  Therapeutics.    Authorized  Translation, 
and  Edited  by  Dr.  Charles  A.  Oliver.  $i  75 

PHILLIPS.      Spectacles  and  Eyeglasses.      Their  Prescription 
and  Adjustment.     2d  Edition.     49  Illustrations.  $1.00 

S WANZY.     Diseases  of  the  Eye  and  Their  Treatment.     7th 

Edition,  Revised  and   Enlarged.     164   Illustrations,  1   Plain    Plate, 
and  a  Zephyr  Test  Card.    Just  Ready.  $2.50 

THORINGTON.    Retinoscopy.    3d  Edition.     Illustrated.       $1.00 

THORINGTON.     Refraction  and  How  to  Refract.    200  Illustra- 
tions, 13  of  which  are  Colored.     2d  Edition.    Just  Ready.  $1.50 

WALKER.      Students'  Aid  in  Ophthalmology.      Colored  Plate 
and  40  other  Illustrations  and  Glossary.  $i-S° 

WRIGHT.     Ophthalmology.     2d  Edition,  Revised  and  Enlarged. 
With  new  Illustrations.  In  Press. 


FEVERS. 

COLLIE.  On  Fevers.  Their  History,  Etiology,  Diagnosis,  Prog- 
nosis, and  Treatment.    Colored  Plates.  $2.00 

GOODALL  AND  WASHBOURN.  Fevers  and  Their  Treat- 
ment.    Illustrated.  $3-°° 

GOUT  AND  RHEUMATISM. 

DUCKWORTH.  A  Treatise  on  Gout.  With  Chromo-lithographs 
and  Engravings.  Cloth,  $6.00 

HAIG.  Causation  of  Disease  by  Uric  Acid.  A  Contribution  to 
the  Pathology  of  High  Arterial  Tension.  Headache,  Epilepsy,  Gout, 
Rheumatism,  Diabetes,  etc.     5th  Edition.    Just  Ready.  $3  00 

HEART. 

SANSOM.  Diseases  of  the  Heart.  The  Diagnosis  and  Pathology 
of  Diseases  of  the  Heart  and  Thoracic  Aorta.  With  Plates  and  other 
Illustrations.  $6.00 

THORNE.  The  Schott  Methods  of  the  Treatment  of  Chronic 
Heart  Disease.     Third  Edition.     Illustrated.    Just  Ready.    $1  75 

HISTOLOGY. 

STIRLING.  Outlines  of  Practical  Histology.  368  Illustrations. 
2d  Edition.  Revised  and  Enlarged.     With  new  Illustrations.       $2.00 

STOHR.  Histology  and  Microscopical  Anatomy.  Translated 
and  Edited  by  A.Schaper,  m.d.,  Harvard  Medical  School.  Second 
American  from  7th  German  Edition,  Revised  and  Enlarged.  292 
Illustrations.  $3-°° 


MEDICAL  BOOKS.  11 


HYGIENE  AND  WATER  ANALYSIS. 

Special  Catalogue  of  Books  on  Hygiene  sent  free  upon  application. 

CANFIELD.  Hygiene  of  the  Sick-Room.  A  Book  for  Nurses 
and  Others.  Being  a  Brief  Consideration  of  Asepsis,  Antisepsis,  Dis- 
infection, Bacteriology,  Immunity,  Heating,  Ventilation,  etc.       $1.25 

COPLIN.  Practical  Hygiene.  A  Complete  American  Text-Book. 
138  Illustrations.     New  Edition.  Preparing . 

ERNST.     Prophylaxis  and  Personal  Hygiene.  In  Press. 

HARTSHORNE.     Our  Homes.     Illustrated.  .40 

KENWOOD.  Public  Health  Laboratory  Work.  116  Illustra- 
tions and  3  Plates.  $2.00 

LEFFMANN.  Examination  of  Water  for  Sanitary  and 
Technical  Purposes.     4th  Edition.     Illustrated.  $x-25 

LEFFMANN.  Analysis  of  Milk  and  Milk  Products.  Illus- 
trated.    Second  Edition  $1.25 

LINCOLN.     School  and  Industrial  Hygiene.  .40 

McNEILL.  The  Prevention  of  Epidemics  and  the  Construc- 
tion and  Management  of  Isolation  Hospitals.  Numerous  Plans 
and  Illustrations.  $3.50 

NOTTER.  The  Theory  and  Practice  of  Hygiene.  15  Plates 
and  138  other  Illustrations.     8vo.     2d  Edition.    Just  Ready.       #7.00 

PARKES.  Hygiene  and  Public  Health.  By  Louis  C.  Parkes, 
m.d.     5th  Edition.     Enlarged.     Illustrated.  $2.50 

PARKES.  Popular  Hygiene.  The  Elements  of  Health.  A  Book 
for  Lay  Readers.     Illustrated.  #1.25 

STARR.  The  Hygiene  of  the  Nursery.  Including  the  General 
Regimen  and  Feeding  of  Infants  and  Children,  and  the  Domestic 
Management  of  the  Ordinary  Emergencies  of  Early  Life,  Massage, 
etc.     6th  Edition.     25  Illustrations.  #1.00 

STEVENSON  AND  MURPHY.  A  Treatise  on  Hygiene.  By 
Various  Authors.     In    Three    Octave    Volumes.     Illustrated. 

Vol.  I,  #6.00;  Vol.  II,  $6.00;  Vol.  Ill,  $5.00 
***  Each  Volume  sold  separately.   Special  Circular  upon  application. 

THRESH.     Water  and  Water  Supplies.     2d  Edition.  #2.00 

WILSON.     Hand-Book    of  Hygiene  and   Sanitary    Science. 

Wiih  Illustrations.     8th  Edition.  $3.00 

WEYL.  Sanitary  Relations  of  the  Coal-Tar  Colors.  Author- 
ized Translation  by  Henry   LEFFM ANN,  M.D.,  PH.D.  $1.25 


LUNGS  AND  PLEURA. 

HARRIS  AND  BEALE.  Treatment  of  Pulmonary  Consump- 
tion. $2.50 

KNOPF.  Pulmonary  Tuberculosis.  Its  Modern  Prophylaxis 
and  Treatment  in  Special  Institutions  and  at  Home.     Illus.        $3  00 

POWELL.  Diseases  of  the  Lungs  and  Pleurae,  including 
Consumption.     Colored  Plates  and  other  Illus.     4th  Ed.         $4.00 


12  SUBJECT   CATALOGUE. 

MASSAGE. 

KLEEN,  Hand-Book  of  Massage.  Authorized  translation  by 
Mussey  Hartwell,  m.d.,  ph.d.  With  an  Introduction  by  Dr.  S. 
Weir  Mitchell.  Illustrated  by  a  series  ot  Photographs  Made 
Especially  by  Dr.  Kleen  for  the  American  Edition.  #2.25 

OSTROM.  Massage  and  the  Original  Swedish  Move- 
ments. Their  Application  to  Various  Diseases  of  the  Body.  A 
Manual  for  Students,  Nurses,  and  Physicians.  Fourth  Edition,  En- 
larged.    105  Illustrations,  many  of  which  are  original.  $1.00 

MITCHELL  AND  GULICK.  Mechanotherapy.  Illus.  In  Press. 
WARD.     Notes  on  Massage.     Interleaved.  Paper  cover,  $1.00 


MATERIA    MEDICA    AND     THERA- 
PEUTICS. 

BIDDLE.  Materia  Medica  and  Therapeutics.  Including  Dose 
List,  Dietary  for  the  Sick,  Table  of  Parasites,  and  Memoranda  of 
New  Remedies.  13th  Edition,  Revised.  64  Illustrations  and  a 
Clinical  Index.  Cloth,  #4.00;  Sheep,  #5.00 

BRACKEN.    Outlines  of  Materia  Medica  and  Pharmacology.    $2.75 

COBLENTZ.  The  Newer  Remedies.  Including  their  Synonyms, 
Sources,  Methods  of  Preparation,  Tests,  Solubilities,  Doses,  etc. 
3d  Edition,  Enlarged  and  Revised.  $1.00 

COHEN.  Physiologic  Therapeutics.  Mechanotherapy,  Mental 
Therapeutics,  Electrotherapy,  Climatology,  Hydrotherapy,  Pneumo- 
theiapy,  Prophylaxis,  Alimentotherapy,  etc.  In  Press. 

DAVIS.    Materia  Medica  and  Prescription  Writing.        gi.50 

GORGAS.  Dental  Medicine.  A  Manual  of  Materia  Medica  and 
Therapeutics.     6th  Edition,  Revised.  #4.00 

GROFF.  Materia  Medica  for  Nurses,  with  questions  for  Self  Exam- 
ination and  a  complete  Glossary.  $1.25 

HELLER.  Essentials  of  Materia  Medica,  Pharmacy,  and 
Prescription  Writing.  $1.50 

MAYS.    Theine  in  the  Treatment  of  Neuralgia.     %  bound,  .50 

POTTER.  Hand-Book  of  Materia  Medica,  Pharmacy,  and 
Therapeutics,  including  the  Action  of  Medicines,  Special  Therapeu- 
tics, Pharmacology,  etc.,  including  over  600  Prescriptions  and  For- 
mulae 7th  Edition,  Revised  and  Enlarged.  With  Thumb  Index  in 
each  copy.  Cloth,  $5.00;   Sheep,  #6.co 

POTTER.  Compend  of  Materia  Medica,  Therapeutics,  and 
Prescription  Writing,  with  Special  Reference  to  the  Physiologi- 
cal Action  of  Drugs.     6th  Edition.  .80;  Interleaved,  $1. 00 


MEDICAL  BOOKS.  13 


SAYRE.     Organic  Materia  Medica  and  Pharmacognosy.    An 

Introduction  to  the  Study  of  the  Vegetable  Kingdom  and  the  Vege- 
table and  Animal  Drugs.  Comprising  the  Botanical  and  Physical 
Characteristics.  Source,  Constituents,  and  Pharmacopeial  Prepara- 
tions, Insects  Injurious  to  Drugs,  and  Pharmacal  Botany.  With 
sections  on  Histology  and  Microtechnique,  by  W.  C.  Stevens. 
374  Illustrations,  many  of  which  are  original.    2d  Edition. 

Cloth,  $4.50 

WHITE  AND  WILCOX.  Materia  Medica,  Pharmacy,  Phar- 
macology, and  Therapeutics.  4th  American  Edition,  Revised  by 
Reynold  W.  Wilcox,  m.a.,  m  d.,  ll.d  ,  Professor  of  Clinical 
Medicine  and  Therapeutics  at  the  New  York  Post-Graduate  Medical 
School.  Cloih.fooo;  Leather,  $3.50 

"  The  care  with  which  Dr.  Wilcox  has  performed  his  work  is  con- 
spicuous on  every  page,  and  it  is  evident  that  no  recent  drug  possess- 
ing any  merit  has  escaped  his  eye.  We  believe,  on  the  whole,  this  is 
the  best  book  on  Materia  Medica  and  Therapeutics  to  place  in  the 
hands  of  students,  and  the  practitioner  will  find  it  a  most  satisfactory 
work  for  daily  use." —  The  Cleveland  Medical  Gazette. 


MEDICAL    JURISPRUDENCE     AND 
TOXICOLOGY. 

REESE.   Medical  Jurisprudence  and  Toxicology.  A  Text-Book 

for    Medical   and    Legal    Practitioners   and  Students.     5th   Edition. 
Revised  by  Henry  Leffmann,  m.d.       Clo.,$3.oo;  Leather,  #3.50 

"  To  the  student  of  medical  jurisprudence  and  toxicology  it  is  in- 
valuable, as  it  is  concise,  clear,  and  thorough  in  every  respect." — The 
American  Journal  of  the  Medical  Sciences. 

MANN.     Forensic  Medicine  and  Toxicology.     Illus.  $6.50 

TANNER.     Memoranda  of  Poisons.     Their  Antidotes  and  Tests. 
7th  Edition.  .75 


MICROSCOPY. 

CARPENTER.     The  Microscope  and    Its    Revelations.    8th 

Edition.     800  Illustrations  and  many  Lithographs.  Preparing. 

LEE.  The  Microtomist's  Vade  Mecum.  A  Hand-Book  ol 
Methods  of  Microscopical  Anatomy.  887  Articles.  5th  Edition, 
Enlarged.    Just  Ready.  $4-°° 

REEVES.  Medical  Microscopy,  including  Chapters  on  Bacteri- 
ology, Neoplasms,  Urinary  Examination,  etc.  Numerous  Illus- 
trations, some  of  which  are  printed  in  colors.  $2.50 

WETHERED.    Medical  Microscopy.    A  Guide  to  the  Use  of  the 

Microscope  in  Practical  Medicine.     100  Illustrations.  $2.00 


14  SUBJECT  CATALOGUE. 

MISCELLANEOUS. 

BRAMWELL.     Anaemia.  $2.50 

BURNETT.  Foods  and  Dietaries.  A  Manual  of  Clinical  JJiet- 
etics.     2d  Edition.  $1.50 

BUXTON.     Anaesthetics.     Illustrated.    3d  Edition.  $1.50 

COHEN.     Organotherapy.  In  Press. 

DAVIS.     Alimentotherapy.  hi  Press. 

FEN  WICK.     Ulcer  of  the  Stomach.     42  Illustrations.  $3.50 

GOULD.  Borderland  Studies.  Miscellaneous  Addresses  and 
Essays.     i2mo.  $2.co 

GREENE.     Medical  Examination  for  Life  Insurance.     Illus- 
trated. Si-oo 
HAIG.     Causation  of  Disease  by  Uric  Acid.     The  Pathology  of 
High  Arterial  Tension,  Headache,  Epilepsy,  Gout.    Rheumatism, 
Diabetes,  Bright's  Disease,  etc.     5th  Edition.    Just  Ready.        $3-co 
HAIG.     Diet  and  Food.     Considered  in  Relation  to  Strength  and 
Power  of  Endurance.     2d  Edition.                                                     $1.00 
HEMMETER.     Diseases  of  the  Stomach.    Their  Special  Path- 
ology .  Diagnosis,  and  Treatment.     With  Sections  on  Anatomy,  Diet- 
etics, Surgery,  etc.    2d  Edition,  Revised  and  Enlarged.     Illustrated. 
Tust  Ready                                                        Cloth,  $6.00;  Sheep,  $7.00 
HEMMETER.     Intestines.     Illustrated.                           Preparing. 
HENRY.     A  Practical  Treatise  on  Anemia.          Halt  Cloth,  .50 
MARSHALL.     History  of  Woman's  Medical  College  of  Penn- 
sylvania.                                                                                            $1-50 
MATAS.     Anesthesia  with   Cocain,  Eucain,    etc.     Local   and 
Regional.     Illustrated.                                                           Nearly  Ready. 
NEW  SYDENHAM  SOCIETY'S  PUBLICATIONS,    circulars 
upon  application.                                                                 Per  Annurq^  $8.00 
OSGOOD.     The  Winter  and  Its  Dangers.  .40 
OSLER    AND    McCRAE.      Cancer    of   the    Stomach.     Just 
Ready.                                                                                                           £2.00 
PACKARD.     Sea  Air  and  Sea  Bathing.  .40 
RICHARDSON.     Long  Life  and  How  to  Reach  It.                  .40 
ST.  CLAIR.     Medical  Latin.                                                          $1.00 
TESSIER.     Pneumotherapy.                                                    In  Press. 
TREVES.    Physical  Education  :  Its  Effects.  Methods.  Etc.  .75 
TURNBULL.    Artificial  Anaesthesia.    4th  Edition.    Illus.    $2.50 
WEBER  AND  HINSDALE.     Climatology.                     In  Press. 
WILSON.     The  Summer  and  Its  Diseases.  .40 
WINTERNITZ.     Hydrotherapy.                                         In  Press. 

NERVOUS  DISEASES. 

BEEVOR.  Diseases  of  the  Nervous  System  and  their  Treat- 
ment. $2.50 

DERCUM.    Rest,  Hypmotism,  Mental  Therapeutics.  In  Press. 

GORDINIER.  The  Gross  and  Minute  Anatomy  of  the  Cen- 
tral Nervous  System.  With  271  original  Colored  and  other 
Illustrations.  Cloth,  $6  00;  Sheep,  $7x0 

GOWERS.  Manual  of  Diseases  of  the  Nervous  System.  A 
Complete  Text-Book.  Revised,  Enlarged,  and  in  many  parts  Re- 
written. With  many  new  Illustrations.  Two  volumes. 
Vol.  I.  Diseases  of  the  Nerves  and  Spinal  Cord.  3d  Edition,  En- 
larged. Cloth,  $4.00  ;  Sheep,  $$. 00 
Vol.  II.  Diseases  r  he  Brain  and  Cranial  Nerves;  General  and 
Functional  Disea~        2d  Edition.              Cloth,  $4.00;  Sheep,  $5.00 

GOWERS.     Syphilis  and  the  Nervous  System.  $1.00 


MEDICAL  BOOKS.  15 

GOWERS.  Clinical  Lectures.  A  New  Volume  of  Essays  on  the 
Diagnosis,  Treatment,  etc.,  of  Diseases  of  the  Nervous  System.  $2.00 

GOWERS.  Epilepsy  and  Other  Chronic  Convulsive  Diseases. 
2d  Edition.  In  Press. 

HORSLEY.  The  Brain  and  Spinal  Cord.  The  Structure  and 
Functions  of.     Numerous  Illustrations.  t2S° 

ORMEROD.  Diseases  of  the  Nervous  System.  66  Wood  En- 
gravings. Ji.oo 

OSLER.     Chorea  and  Choreiform  Affections.  $2.00 

PRESTON.  Hysteria  and  Certain  Allied  Conditions.  Their 
Nature  and  Treatment.     Illustrated.  $2.00 

WOOD.     Brain  Work  and  Overwork.  40 

NURSING  (see  also  Massage). 

Special  Catalogue  of  Books  for  Nurses  sent  free  upon  application. 

BROWN.     Elementary  Physiology  for  Nurses.  .75 

CANFIELD.  Hygiene  of  the  Sick-Room.  A  Book  for  Nurses  and 
Others.  Being  a  Brief  Consideration  of  Asepsis,  Antisepsis,  Disinfec- 
tion, Bacteriology,  Immunity,  Heating  and  Ventilation,  and  Kindred 
Subjects  for  the  Use  of  Nurses  and  Other  Intelligent  Women.     $1.25 

CUFF.     Lectures  to  Nurses  on  Medicine.    New  Edition.     $1.25 

DOMVILLE.     Manual  for  Nurses  and  Others  Engaged  in  At- 
tending the  Sick.    8th  Edition.  With  Recipes  for  Sick-room  Cook- 
ery, etc.  -75 
FULLERTON.     Obstetric  Nursing.     41  Ills.     5th  Ed.           $1.00 
FULLERTON.      Surgical    Nursing.     3d  Ed.     69  Ills.           $1.00 
GROFF.     Materia  Medica  for  Nurses.     With  Questions  for  Self-Ex- 
amination  and  a  very  complete  Glossary.                                          $1-25 
"  It  will  undoubtedly  prove  a  valuable  aid  to  the  nurse  in  securing  a 
knowledge   of   drugs   and   their   uses."—  The  Medical  Record,   New 
York. 

HORWITZ.     Duties  of  the  Surgical  Nurse.  In  Press. 

HUMPHREY.  A  Manual  for  Nurses.  Including  General 
Anatomy  and  Physiology,  Management  of  the  Sick  Room,  etc. 
17th  Ed.     Illustrated.  $1.00 

"  In  the  fullest  sense,  Dr.  Humphrey's  book  is  a  distinct  advance  on 
all   previous   manuals.     It   is,  in  point   of  fact,  a  concise  treatise  on 
medicine  and  surgery  for  the  beginner,  incorporating  with  the  text  the 
management  of  childbed  and  the  hygiene  of  the  sick-room.     Its  value 
is  greatly  enhanced  by  copious  wood-cuts  and  diagrams  of  the  bones 
and  internal  organs." — British  Medical  Journal ,  London. 
STARR.     The  Hygiene  of  the  Nursery.     Including  the  General 
Regimen  and  Feeding  of  Infants  and  Children,  and  the  Domestic  Man- 
agement of  the  Ordinary  Emergencies  of  Early  Life,  Massage,  etc.  6th 
Edition.     25  Illustrations.  $1.00 

TEMPERATURE  AND  CLINICAL  CHARTS.     See  page  6. 

VOSWINKEL.     Surgical   Nursing.     Second  Edition,  Enlarged. 

112  Illustrations.  $1.00 

WESTLAND.     The  Wife  and  Mother.  $1.50 


16  SUBJECT  CATALOGUE 

OBSTETRICS. 

CAZEAUX  AND  TARNIER.  Midwifery.  With  Appendix  by 
Mund6.  The  Theory  and  Practice  of  Obstetrics,  including  the  Dis- 
eases ot  Pregnancy  and  Parturition,  Obstetrical  Operations,  etc. 
8th  Edition.  Illustrated  by  Chromo-Lithographs,  Lithographs,  and 
other  full-page  Plates,  seven  of  which  are  beautifully  colored,  and 
numerous  Wood  Engravings.  Cloth,  $4.50;  Full  Leather,  $5.50 

DAVIS.     A  Manual  of  Obstetrics.     3d  Edition.  Preparing. 

EDGAR.     Text-Book  of  Obstetrics.     Illustrated.        Preparing. 

LANDIS.  Compend  of  Obstetrics.  6th  Edition,  Revised  by  Wm. 
H.  Wells,  Assistant  Demonstrator  of  Clinical  Obstetrics,  Jefferson 
Medical   College.     With  47   Illustrations,    .80;    Interleaved,     #i.go 

WINCKEL.  Text-Book  of  Obstetrics,  Including  the  Pathol- 
ogy and  Therapeutics  of  the  Puerperal  State.  Authorized 
Translation  by  J.  Clifton  Edgar,  a.m.,  m.d.  With  nearly  200  Illus- 
trations. Cloth,  $5.00;  Leather,  $6.00 

FULLERTON.    Obstetric  Nursing.     5th  Ed.    Illustrated.    $1.00 

PATHOLOGY. 

BARLOW.     General  Pathology.     795  pages.    8vo.  $5.00 

BLACK.     Micro-Organisms.     The  Formation  of  Poisons.  .75 

BLACKBURN.     Autopsies.     A  Manual  of  Autopsies  Designed  for 

the  Use  ot  Hospitals  for  the  Insane  and  other  Public  Institutions. 

Ten  full-page  Plates  and  other  Illustrations.  $*-z5 

COMPEND  of  General  Pathology.     Illustrated.  Preparing. 

COPLIN.  Manual  of  Pathology.  Including  Bacteriology,  Technic 
of  Post-Mortems,  Methods  of  Pathologic  Research,  etc.  330  Illus- 
trations, 7  Colored  Plates,  many  of  which  are  original.  3d  Edition. 
Just  Ready.  $3-5° 

DA  COSTA.     Clinical  Pathology  of  the  Blood.    Ilius.    In  Press. 
GILLIAM.     Pathology.  A  Hand-Book  for  Students.  47  Illus.     .75 
HEWLETT.     Manual  of  Bacteriology.     75  Illustrations.    $3.00 
VIRCHOW.     Post-Mortem  Examinations.     A  Description  and 
Explanation  of  the  Method  of  Performing  Them  in  the  Dead  House 
of  the  Berlin  Charity  Hospital,  with  Special  Reference  to  Medico- 
Legal  Practice.     3d  Edition,  with  Additions.  .75 

WHITACRE.     Laboratory  Text-Book   of  Pathology.     With 

121  Illustrations.  $x-5° 

WILLIAMS.  Bacteriology.  A  Manual  for  Students.  78  Illus- 
trations. $1.50 

PHARMACY. 

Special  Catalogue  of  Books  on  Pharmacy  sent  free  upon  application. 

COBLENTZ.  Manual  of  Pharmacy.  A  Complete  Text-Book 
by  the  Professor  in  the  New  York  College  of  Pharmacy.  «d  Edition. 
Revised  and  Enlarged.   437  Illus.  Cloth,  $3.50;  Sheep,  $4  5c 

BEASLEY.  Book  of  3100  Prescriptions.  Collected  from  th< 
Practice  of  the  Most  Eminent  Physicians  and  Surgeons — English 
French,  and  American.  A  Compendious  History  ot  the  Materia 
Medica,  Lists  of  the  Doses  of  all  the  Officinal  and  Established  Pre- 
parations, an  Irdexof  Diseases  and  their  Remedies.     7th  Ed.     $2.00 


MEDICAL   BOOKS.  17 


BEASLEY.  Druggists'  General  Receipt  Book.  Comprising 
a  Copious  Veterinary  Formulary,  Recipes  in  Patent  and  Proprietary 
Medicines,  Druggists'  Nostrums,  etc. ;  Perfumery  and  Cosmetics, 
Beverages,  Dietetic  Articles  and  Condiments,  Trade  Chemicals, 
Scientific  Processes,  and  many  Useful  Tables,     ioth  Ed.  $2.00 

BEASLEY.  Pharmaceutical  Formulary.  A  Synopsis  of  the 
British,  French,  German,  and  United  States  Pharmacopoeias.  Com- 
prising Standard  and  Approved  Formulae  for  the  Preparations  and 
Compounds  Employed  in  Medicine.     12th  Edition.  $2.00 

PROCTOR.  Practical  Pharmacy.  Lectures  on  Practical  Phar- 
macy. With  Wood  Engravings  and  32  Lithographic  Fac-simile 
Prescriptions.  3d  Edition,  Revised,  and  with  Elaborate  Tables  of 
Chemical  Solubilities,  etc.  $3.00 

ROBINSON.  Latin  Grammar  of  Pharmacy  and  Medicine. 
3d  Edition.     With  elaborate  Vocabularies.  J>I-75 

SAYRE.  Organic  Materia  Medica  and  Pharmacognosy.  An 
Introduction  to  the  Study  of  the  Vegetable  Kinedom  and  the  Vege- 
table and  Animal  Drugs.  Comprising  the  Botanical  and  Physical 
Characteristics,  Source,  Constituents,  and  Pharmacopeial  Prepar- 
ations, Insects  Injurious  to  Drugs,  and  Parmacal  Botany.  With 
sections  on  Histology  and  Microtechnique,  by  W.  C.  Stevens. 
374  Illustrations.     Second  Edition.  Cloth,  $4.50 

SCOVILLE.  The  Art  of  Compounding.  Second  Edition,  Re- 
vised and  Enlarged.  Cloth,  $2.50 

STEWART.  Compend  of  Pharmacy.  Based  upon  "  Reming- 
ton's Text-Book  of  Pharmacy."  5th  Edition,  Revised  in  Accord- 
ance with  the  U.  S.  Pharmacopoeia,  1890.  Complete  Tables  of 
Metric  and  English  Weights  and  Measures.     .80;    Interleaved,  $1.00 

UNITED  STATES  PHARMACOPOEIA.  7th  Decennial  Revision. 
Cloth,  $2.50  (postpaid,  $2.77) ;  Sheep,  $3.00  (postpaid,  $3.27) ;  Inter- 
leaved, $4.00  (postpaid,  #4.50);  Printed  on  one  side  of  page  only, 
unbound,  $3.50  (postpaid,  $3.90). 

Select  Tables  from  the  U.  S.  P.  Being  Nine  of  the  Most  Impor- 
tant and  Useful  Tables,  Printed  on  Separate  Sheets.  Carefully 
put  up  in  patent  envelope.  .25 

POTTER.  Hand-Book  of  Materia  Medica,  Pharmacy,  and 
Therapeutics.    600  Prescriptions.    7th  Ed.    Clo.,$5.oo;  Sh.,  $6.00 

PHYSICAL  DIAGNOSIS. 

BROWN.  Medical  Diagnosis.  A  Manual  of  Clinical  Methods. 
4th  Edition.     112  Illustrations.  Cloth,  $2.25 

DA  COSTA.     Clinical  Examination  of  the  Blood.    Illustrated. 

In  Press. 

FENWICK.  Medical  Diagnosis.  8th  Edition.  Rewritten  and 
very  much  Enlarged.     135  Illustrations.  Cloth,  $2.50 

MEMMINGER.   Diagnosis  by  the  Urine.   2d  Ed.   24  Illus.  $1  00 

TYSON.  Hand-Book  of  Physical  Diagnosis.  For  Students  and 
Physicians.  By  the  Professor  of  Clinical  Medicine  in  the  University 
of  Pennsylvania.  Illus.  3d  Ed.,  Improved  and  Enlarged.  With 
Colored  and  other  Illustrations.  #i-5° 

PHYSIOLOGY. 

BIRCH.      Practical    Physiology.     An   Elementary  Class  Book. 

62  Illustrations.  $t-75 

BRUBAKER.    Compend  of  Physiology,     ioth  Edition,  Revised 

and  Enlarged.     Illustrated.    Just  Ready.         .80;  Interleaved,  $1.00 

2 


18  SUBJECT  CATALOGUE. 

KIRKES.  Physiology.  (16th  Authorized  Edition.  Dark-Red  Cloth.) 
A  Hand-Book  of  Physiology.  16th  Edition,  Revised,  Rearranged, 
and  Enlarged.  By  Prof.  W.  D.  Halliburton,  of  Kings  College, 
London.  671  Illustrations,  some  of  which  are  printed  in  colors. 
Just  Ready.  Cloth,  $3.00;  Leather,  $3.75 

LANDOIS.  A  Text-Book  of  Human  Physiology,  Including 
Histology  and  Microscopical  Anatomy,  with  Special  Reference  to 
the  Requirements  of  Practical  Medicine.  5th  American,  translated 
from  the  9th  German  Edition,  with  Additions  by  Wm.  Stirling, 
M.D.,D.sc.    845  Illus.,  many  of  which  are  printed  in  colors.   In  Press. 

STARLING.     Elements  of  Human  Physiology.     100  Ills.    $1.00 

STIRLING.  Outlines  of  Practical  Physiology.  Including 
Chemical  and  Experimental  Physiology,  with  Special  Reference  to 
Practical  Medicine.     3d  Edition.     289  Illustrations.  $2.00 

TYSON.     Cell  Doctrine.     Its  History  and  Present  State.        $1.50 

PRACTICE. 

BEALE.     On  Slight  Ailments;  their  Nature  and  Treatment. 

2d  Edition,  Enlarged  and  Illustrated.  $!-25 

FOWLER.  Dictionary  of  Practical  Medicine.  By  various 
writers.  An  Encyclopaedia  of  Medicine.  Cio.,$3.oo:  Half  Mor.  £4.00 
GOULD  AND  PYLE.  Cyclopedia  of  Practical  Medicine  and 
Surgery.  A  Concise  Reference  Handbook,  Alphabetically 
Arranged,  with  particular  Reference  to  Diagnosis  and  Treatment. 
Edited  by  Drs.  Gould  and  Pyle,  Assisted  by  72  Special  Con- 
tributors. Illustrated,  one  volume.  Large  Square  Octavo,  Uniform 
with  *'  Gould's  Illustrated  Dictionary."    Just  Ready. 

Sheep  or  Half  Morocco,  $-0.00:  with  Thumb  Index,  $n«oo 
Half  Russia,  Thumb  Index,  $12  00 
4^*  Complete  descriptive  circular  with  sample  pages  and  illustra- 
tions of  this  book  will  be  sent  free  upon  application. 

HUGHES.  Compend  of  the  Practice  of  Medicine.  6th  Edition, 
Revised  and  Enlarged.    Just  Ready. 

Part  I.     Continued,  Eruptive,  and  Periodical  Fevers,  Diseases  of  the 
Stomach,    Intestines,  Peritoneum,  Biliary    Passages,  Liver,  Kid- 
neys, etc.,  and  General  Diseases,  etc. 
Part  II.     Diseases  of  the  Respiratory  System,  Circulatory  System, 
and  Nervous  System;  Diseases  of  the  Blood,  etc. 

Price  of  each  part,  .80;  Interleaved,  $1.00 
Physician's   Edition.      In  one  volume,  including  the  above  two 
parts,  a   Section  on  Skin    Diseases,  and  an  Index.     6th   Revised 
Edition.     625  pp.    Just  Ready.        Full  Morocco,  Gilt  Edge,  $2.25 
TAYLOR.     Practice  of  Medicine,     sthrdition.  Cloth,  $4.00 

TYSON.  The  Practice  of  Medicine.  By  James  Tyson,  m.d., 
Professor  of  Medicine  in  the  University  of  Pennsylvania.  A  Com- 
plete Systematic  Text-book  with  Special  Reference  to  Diagnosis  and 
Treatment.  2d  Edition,  Enlarged  and  Revised.  Colored  Plates  and 
125  other  Illustrations.     1222  Pages.     8vo.    Just  Ready. 

Cloth,  $5.50;  Leather,  $6. 50 

PRESCRIPTION  BOOKS. 

BEASLEY.  Book  of  3100  Prescriptions.  Collected  from  the 
Practice  of  the  Most  Eminent  Physicians  and  Surgeons — English, 
French,  and  American.  A  Compendious  History  of  the  Materia, 
Medica,  Lists  of  the  Doses  of  all  Officinal  and  Established  Prepara- 
tions, and  an  Index  of  Diseases  and  their  Remedies.     7th  Ed.     $2.00 


MEDICAL   BOOKS.  19 


BEASLEY.  Druggists'  General  Receipt  Book.  Comprising 
a  Copious  Veterinary  Formulary,  Recipes  in  Patent  and  Proprie- 
tary Medicines,  Druggists'  Nostrums,  etc.  ;  Perfumery  and  Cos- 
metics, Beverages,  Dietetic  Articles  and  Condiments,  Trade  Chem- 
icals, Scientific  Processes,  and  an  Appendix  of  Useful  Tables, 
ioth  Edition,  Revised.  #2.00 

BEASLEY.  Pocket  Formulary.  A  Synopsis  of  the  British,  French, 
German,  and  United  States  Pharmacopoeias  and  the  chief  unofficial 
Formularies.     12th  Edition.  $2.00 

SKIN. 

BULKLEY.    The  Skin  in  Health  and  Disease.    Illustrated.    .40 

CROCKER.  Diseases  of  the  Skin.  Their  Description,  Pathol- 
ogy, Diagnosis,  and  Treatment,  with  Special  Reference  to  the  Skin 
Eruptions  of  Children.   92  Illus.   3d  Edition.  Preparing. 

IMPEY.     Leprosy.     37  Plates.     8vo.  £3.50 

SCHAMBERG.  Diseases  of  the  Skin.  2d  Edition,  Revised  and 
Enlarged.  105  Illustrations.  Being  No.  16  ?  Quiz-Compend?  Series. 
Just  Ready.  Cloth,  .80;  Interleaved,  #1.00 

VAN  HARLINGEN.  On  Skin  Diseases.  A  Practical  Manual 
of  Diagnosis  and  Treatment,  with  special  reference  to  Differential 
Diagnosis.  3d  Edition,  Revised  and  Enlarged.  With  Formulae 
and  60  Illustrations,  some  of  which  are  printed  in  colors.        $2.75 

SURGERY  AND  SURGICAL   DIS- 
EASES (see  also  Urinary  Organs). 

BUTLIN.  Operative  Surgery  of  Malignant  Disease.  2d  Edi- 
tion.    Illustrated.     Octavo.    Just  Ready.  $4-5° 

CRIPPS.  Ovariotomy  and  Abdominal  Surgery.  Illus.  $8.00 
DEAVER.  Surgical  Anatomy.  A  Treatise  on  Human  Anatomy 
in  its  Application  to  Medicine  and  Surgery.  With  about  400  very 
Handsome  full-page  Illustrations  Engraved  from  Original  Drawings 
made  by  special  Artists  from  Dissections  prepared  for  the  purpose. 
Three  Volumes.     Royal  Square  Octavo. 

Cloth,  #21.00  ;  Half  Morocco  or  Sheep,  #24.00  ;  Half  Russia,  $27.00 
Complete  descriptive  circular  and  special  tertns  upon  application. 

DEAVER.  Appendicitis,  Its  Symptoms,  Diagnosis,  Pathol- 
°gy»  Treatment,  and  Complications.  Elaborately  Illustrated 
with  Colored  Plates  and  other  Illustrations.     2d  Edition.  #3-5o 

DULLES.  What  to  Do  First  in  Accidents  and  Poisoning. 
5th  Edition.     New  Illustrations.  #1.00 

FULLERTON.     Surgical  Nursing.     3d  Edition.    69  Illus.    $1  00 

HAMILTON.  Lectures  on  Tumors,  from  a  Clinical  Stand- 
point.    Third  Edition,  Revised,  with  New  Illustrations.  $1.25 

HEATH.  Minor  Surgery  and  Bandaging,  nth  Ed.,  Revised 
and  Enlarged.     176  Illustrations,   Formulae,  Diet  List,  etc.      #1.25 

HEATH.  Injuries  and  Diseases  of  the  Jaws.  4th  Edition. 
187  Illustrations.  $4-5° 

HEATH.  Lectures  on  Certain  Diseases  of  the  Jaws.  64 Illus- 
trations. Boards,  .50 


20  SUBJECT  CATALOGUE. 

HORWITZ.  Compend  of  Surgery  and  Bandaging,  including 
Minor  Surgery,  Amputations,  Fractures,  Dislocations,  Surgical  Dis- 
eases, and  the  Latest  Antiseptic  Rules,  etc.,  with  Differential  Diagno- 
sis and  Treatment.  5th  Edition,  very  much  Enlarged  and  Rear- 
ranged.   167  Illustrations,  98  Formulae.   Clo.,  .80;  Interleaved,  $1. 25 

JACOBSON.    Operations    of   Surgery.    Over  200  Illustrations. 

Cloth,  $3.00 ;  Leather,  $4.00 

JACOBSON.     Diseases  of  the   Male   Organs  of  Generation. 

88    Illustrations.  #6.00 

LANE.  Surgery  of  the  Head  and  Neck,  no  Illustrations. 
2d  Edition.  $5.00 

MACREADY.  A  Treatise  on  Ruptures.  24  Full-page  Litho- 
graphed Plates  and  Numerous  Wood  Engravings.  Cloth,  $6.00 

MAYLARD.  Surgery  of  the  Alimentary  Canal.  97  Illustrations. 
2d  Edition,  Revised.    Just  Ready.  $3.00 

MOULLIN.  Text-Book  of  Surgery.  With  Special  Reference  to 
Treatment.  3d  American  Edition.  Revised  and  edited  by  John  B. 
Hamilton,  m.d.,  ll.d.,  Professor  of  the  Principles  of  Surgery  and 
Clinical  Surgery,  Rush  Medical  College,  Chicago.  623  Illustrations, 
over  200  of  which  are  original,  and  many  of  which  are  printed  in 
colors.  Handsome  Cloth,  $6.00;  Leather,  $7.00 

ROBERTS.  Fractures  of  the  Radius.  A  Clinical  and  Patho- 
logical Study.     33  Illustrations.  $1.00 

SMITH.  Abdominal  Surgery.  Being  a  Systematic  Description  of 
all  the  Principal  Operations.    224  Illus.  6th  Ed.    2  Vols.  Clo.,  $10.00 

SWAIN.     Surgical  Emergencies.     Fifth  Edition.         Cloth,  $1. 75 

VOSWINKEL.  Surgical  Nursing.  Second  Edition,  Revised  and 
Enlarged,     in  Illustrations.  $1.00 

WALSHAM.  Manual  of  Practical  Surgery.  7th  Ed.,  Re- 
vised and  Enlarged.   483  Engravings.   950  pages.  Just  Ready.  $3.50 

THROAT   AND    NOSE   (see  also  Ear). 
COHEN.     The  Throat  and  Voice.     Illustrated.  .40 

HALL.      Diseases    of   the    Nose    and    Throat.     Two    Colored 

Plates  and  59  Illustrations.     New  Edition  Preparing. 

HOLLOPETER.     Hay  Fever.     Its  Successful  Treatment.      $1.00 

KNIGHT.      Diseases  of  the  Throat.     A  Manual  for  Students. 

Illustrated.  Nearly  Ready. 

MACKENZIE.  Pharmacopoeia  of  the  London  Hospital  for 
Dis.  of  the  Throat.    5th  Ed.,  Revised  by  Dr.  F.  G.  Harvey.  $1.00 

McBRIDE.  Diseases  of  the  Throat,  Nose,  and  Ear.  With  col- 
ored Illus.  from  original  drawings.    3d  Ed.    Just  Ready  $7.00 

POTTER.  Speech  arid  its  Defects.  Considered  Physiologically, 
Pathologically,  and  Remedially.  $1.00 


URINE  AND  URINARY  ORGANS. 

ACTON.  The  Functions  and  Disorders  of  the  Reproductive 
Organs  in  Childhood,  Youth,  Adult  Age,  and  Advanced  Life, 
Considered  in  their  Physiological,  Social,  and  Moral  Relations. 
8th  Edition.  $1.75 


MEDICAL   BOOKS.  21 


BEALE.  One  Hundred  Urinary  Deposits.  On  eight  sheets, 
for  the  Hospital,  Laboratory,  or  Surgery.  Paper,  $2.00 

HOLLAND.    The  Urine,  the  Gastric  Contents,  the  Common 
Poisons,  and  the  Milk.     Memoranda,  Chemical  and  Microscopi- 
cal, for  Laboratory  Use.   Illustrated  and  Interleaved.    6th  Ed.    $1.00 
JACOBSON.     Male  Organs  of  Generation.    88  Illus.  $6.00 

KEHR.  Gall-Stone  Disease.  Translated  by  William  Watkyns 
SrymOUR,  m  d.  In  Press. 

KLEEN.     Diabetes  and  Glycosuria.  $2.50 

MEMMINGER.    Diagnosis  by  the  Urine.   2d  Ed.   24  Illus.   #1.00 
MORRIS.     Renal  Surgery,  with  Special  Reference  to  Stone  in  the 
Kidney  and   Ureter  and   to   the  Surgical   Treatment  of  Calculous 
Anuria.     Illustrated.  #2.00. 

MOULLIN.  Enlargement  of  the  Prostate.  Its  Treatment  and 
Radical  Cure.     2d  Edition.     Illustrated.    Just  Ready.  $I-75 

MOULLIN.  Inflammation  of  the  Bladder  and  Urinary  Fever. 
Octavo.  J1.50 

SCOTT.  The  Urine.  Its  Clinical  and  Microscopical  Examination. 
41  Lithographic  Plates  and  other  Illustrations.    Quarto.  Cloth,  #5.00 

TYSON.     Guide  to  Examination  of  the  Urine.     For  the  Use  of 

Physicians  and  Students.     With  Colored  Plate  and  Numerous  Illus- 
trations engraved  on  wood.     9th  Edition,  Revised.  $*-*S 

VAN   NUYS.    Chemical  Analysis  of  Urine.    39  Illus.         $1.00 

VENEREAL  DISEASES. 

COOPER.     Syphilis.    2d    Edition,   Enlarged  and   Illustrated   with 

20  full-page  Plates.  $5-°° 

GOWERS.    Syphilis  and  the  Nervous  System.  1.00 

STURGIS.      Student's   Manual   of   Venereal   Diseases.      7th 

Revised  and  Enlarged  Edition.     i2mo.  In  Press. 

VETERINARY. 

BALLOU.  Veterinary  Anatomy  and  Physiology.  29  Graphic 
Illustrations.  .80;  Interleaved,  $1. 00 

TUSON.  Veterinary  Pharmacopoeia.  Including  the  Outlines  of 
Materia  Medica  and  Therapeutics.    5th  Edition.  #2.25 

WOMEN,  DISEASES  OF. 

BYFORD  (H.  T.).  Manual  of  Gynecology.  Second  Edition, 
Revised  and  Enlarged  by  100  pages.     341  Illustrations.  $3°o 

DUHRSSEN.  A  Manual  of  Gynecological  Practice.  105 
Illustrations.  $1.50 

FULLERTON.  Surgical  Nursing.  3d  Edition,  Revised  and 
Enlarged.     69  Illustrations.  #1.00 

LEWERS.    Diseases  of  Women.    146  Illus.    5th  Ed.  $2.50 

MONTGOMERY.  Practical  Gynecology.  A  Complete  Sys- 
tematic Text-Book.    527  Handsome  Illustrations.    8vo.  Just  Ready. 

Cloth,  $5. 00;  Leather,  $6.00 
WELLS.    Compend  of  Gynecology.    Illustrated.    2d  Edition. 

.80;  Interleaved,  $1.00 


22  SUBJECT  CATALOGUE. 


COMPENDS. 


Front  The  Southern  Clinic 

"  We  know  of  no  series  of  books  issued  by  any  house  that  so  fully 
meets  our  approval  as  these  ?  Quiz-Compends?.  They  are  well  ar- 
ranged, full,  and  concise,  and  are  really  the  best  line  of  text-books  that 
could  be  found  for  either  student  or  practitioner." 


BLAKISTON'S  ?  QUIZ-COMPENDS? 

The  Best  Series  of  Manuals  for  the  Use  of  Students. 
Price  of  each,  Cloth,  .80.         Interleaved,  for  taking  Notes,  $1.00. 

49"  These  Compends  are  based  on  the  most  popular  text-books 
and  the  lectures  of  prominent  professors,  and  are  kept  constantly  re- 
vised, so  that  they  may  thoroughly  represent  the  present  state  of  the 
subjects  upon  which  they  treat. 

4Qf*  The  authors  have  had  large  experience  as  Quiz-Masters  and 
attaches  of  colleges,  and  are  well  acquainted  with  the  wants  of  students. 

49*  They  are  arranged  in  the  most  approved  form,  thorough  and 
concise,  containing  over  6oo  fine  illustrations,  inserted  wherever  they 
could  be  used  to  advantage. 

Can  be  used  by  students  of  any  college. 

They  contain  information  nowhere  else   collected  in  such  a 
condensed,  practical  shape.     Illustrated  Circular  free. 

No.  i.  POTTER.  HUMAN  ANATOMY.  Sixth  Revised  and 
Enlarged  Edition.  Including  Visceral  Anatomy.  Can  be  used 
with  either  Morris's  or  Gray's  Anatomy.  117  Illustrations  and  16 
Lithographic  Plates  of  Nerves  and  Arteries,  with  Explanatory 
Tables,  etc.  By  Samuel  O.  L.  Potter,  m.d.,  Professor  of  the 
Practice  of  Medicine,  College  of  Physicians  and  Surgeons,  San 
Francisco  ;  Brgade  Surgeon,  U.  S.  Vol. 

No.  2.  HUGHES.  PRACTICE  OF  MEDICINE.  Part  I.  Sixth 
Edition,  Enlarged  and  Improved.  By  Daniel  E.  Hughes,  m.d., 
Physician-in-Chief,  Philadelphia  Hospital,  lafe  Demonstrator  of 
Clinical  Medicine,  Jefferson  Medical  College,  Phila. 

No.  3.  HUGHES.  PRACTICE  OF  MEDICINE.  Part  II. 
Sixth  Edition,  Revised  and  Improved.     Same  author  as  No.  2. 

No.  4.  BRUBAKER.  PHYSIOLOGY.  Tenth  Edition,  with 
Illustrations  and  a  table  of  Physiological  Constants.  Enlarged 
and  Revised.  By  A.  P.  Brubaker,  m.d.,  Professor  of  Physiology 
and  General  Pathology  in  the  Pennsylvania  College  of  Dental 
Surgery;  Adjunct  Professor  of  Physiology,  Jefferson  Medical 
College,  Philadelphia,  etc. 

No.  5.  LANDIS.  OBSTETRICS.  Sixth  Edition.  By  Henry  G. 
Landis,  m.d.  Revised  and  Edited  by  Wm.  H.  Wells,  m.d., 
Instructor  of  Obstetrics,  Jefferson  Medical  College,  Philadelphia. 
Enlarged.     47  Illustrations. 

No.  6.  POTTER.  MATERIA  MEDICA,  THERAPEUTICS, 
AND  PRESCRIPTION  WRITING.  Sixth  Revised  Edition 
(U.  S.  P.  1890).  By  Samuel  O.  L.  Potter,  m.d.,  Professor  of 
Practice,  College  of  Physicians  and  Surgeons,  San  Francisco; 
Brigade  Surgeon,  U.  S.  Vol. 


MEDICAL  BOOKS.  23 


PQUIZ-COMPENDS  ?— Continued. 

No.  7.  WELLS.  GYNECOLOGY.  Second  Edition.  ByWM.  H. 
Wells,  m.d.,  Instructor  of  Obstetrics,  JeffersoD  College,  Philadel- 
phia.    140  Illustrations. 

No.  8.  GOULD  AND  PYLE.  DISEASES  OF  THE  EYE 
AND  REFRACTION.  Second  Edition.  Including  Treatment 
and  Surgery,  and  a  Section  on  Local  Therapeutics.  By  George 
M.  Gould,  m.d.,  and  W.  L.  Pyle,  m.d.  With  Formulae,  Glossary, 
Tables,  and  109  Illustrations,  several  of  which  are  Colored. 

No.  9.  HORWITZ.  SURGERY,  Minor  Surgery,  and  Bandag- 
ing. Fifth  Edition,  Enlarged  and  Improved.  By  Orvillb 
Horwitz,  b.  S-,  m.d.,  Clinical  Professor  of  Genito-Urinary  Surgery 
and  Venereal  Diseases  in  Jefferson  Medical  College ;  Surgeon  to 
Philadelphia  Hospital,  etc.    With  98  Formulae  and  71  Illustrations. 

No.  10.  LEFFMANN.      MEDICAL    CHEMISTRY.      Fourth 

Edition.  Including  Urinalysis,  Animal  Chemistry,  Chemistry  of 
Milk,  Blood,  Tissues,  the  Secretions,  etc.  By  Henry  Leffmann, 
m.d.,  Professor  of  Chemistry  in  Pennsylvania  College  of  Dental 
Surgery  and  in  the  Woman's  Medical  College,  Philadelphia. 

No.  11.  STEWART.  PHARMACY.  Fifth  Edition.  Based  upon 
Prof.  Remington's  Text-Book  of  Pharmacy.  By  F.  E.  Stewart, 
m.d.,  ph.g.,  late  Quiz-Master  in  Pharmacy  and  Chemistry,  Phila- 
delphia College  of  Pharmacy ;  Lecturer  at  Jefferson  Medical 
College.     Carefully  revised  in  accordance  with  the  new  U.  S.  P. 

No.  12.  BALLOU.  VETERINARY  ANATOMY  AND  PHY- 
SIOLOGY. Illustrated.  By  Wm.  R.  Ballou,  m.d.,  Professor 
of  Equine  Anatomy  at  New  York  College  of  Veterinary  Surgeons  ; 
Physician  to  Bellevue  Dispensary,  etc.     29  graphic  Illustrations 

No.  13.  WARREN.  DENTAL  PATHOLOGY  AND  DEN- 
TAL MEDICINE.  Third  Edition,  Illustrated.  Containing 
a  Section  on  Emergencies.  By  Geo.  W.  Warren,  d.d.s.,  Chief 
ot  Clinical  Staff,  Pennsylvania  College  of  Dental  Surgery. 

No.  1A.  HATFIELD.  DISEASES  OF  CHILDREN.  Second 
Edition.  Colored  Plate.  By  Marcus  P.  Hatfield,  Profes- 
sor of  Diseases  of  Children,  Chicago  Medical  College. 

No.  15.  GENERAL  PATHOLOGY.     Illustrated  Preparing. 

No.  16.  DISEASES  OF  THE  SKIN.  Second  Edition.  By 
Jay  F.  Schamberg,  m.d.,  Professor  of  Diseases  of  the  Skin, 
Philadelphia  Polyclinic.  Second  Edition,  Revised  and  Enlarged. 
105  handsome  Illustrations. 

Price,  each,  Cloth,  .80.  Interleaved,  for  taking  Notes,  $1.00 

In  preparing,  revising,  and  improving  Blakiston's  ?Quiz-Com- 
pends  ?  the  particular  wants  of  the  student  have  always  been  kept  in 
mind. 

Careful  attention  has  been  given  to  the  construction  of  each  sentence, 
and  while  the  books  will  be  found  to  contain  an  immense  amount  of 
knowledge  in  small  space,  they  will  likewise  be  found  easy  reading ; 
there  is  no  stilted  repetition  of  words ;  the  style  is  clear,  lucid,  and  dis- 
tinct. The  arrangement  of  subjects  is  systematic  and  thorough  ;  there 
Is  a  reason  for  every  word.     They  contain  over  600  illustrations. 


Morris' 
Anatomy 

Second  Edition,  Revised  and  Enlarged. 

790  Illustrations,  of  which  many 
are  in  Colors. 

Royal  Octavo.     Cloth,  $6.00  ;  Sheep,  $7.00  ; 
Half  Russia,  $8.00. 


From  The  Medical  Record,  New  York. 

"  The  reproach  that  the  English  language  can  boast  of  no 
treatise  on  anatomy  deserving  to  be  ranked  with  the  masterly 
works  of  Henle,  Luschka,  Hyrtl,  and  others,  is  fast  losing 
its  force.  During  the  past  few  years  several  works  of  great 
merit  have  appeared,  and  among  these  Morris's  "Anatomy" 
seems  destined  to  take  first  place  in  disputing  the  palm  in 
anatomical  fields  with  the  German  classics.  The  nomencla- 
ture, arrangement,  and  entire  general  character  resemble 
strongly  those  of  the  above-mentioned  handbooks,  while  in 
the  beauty  and  profuseness  of  its  illustrations  it  surpasses 
them.  .  .  .  The  ever-growing  popularity  of  the  book 
with  teachers  and  students  is  an  index  of  its  value,  and  it 
may  safely  be  recommended  to  all  interested." 

From  The  Philadelphia  Medical  Journal. 

"  Of  all  the  text-books  of  moderate  size  on  human  anatomy 
in  the  English  language,  Morris  is  undoubtedly  the  most 
up-to-date  and  accurate." 


V  Handsome  Descriptive  Circular,  with  Sample  Pages  and 
Colored  Illustrations,  will  be  sent  free  upon  application. 


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